Scientific-American-Aug-1-1876, J. A. FAY & CO.'S EXHIBIT OF WOODWORKING MACHINERY AT THE CENTENNIAL

20834 SCIENTIFIC AMERICAN SUPPLEMENT, No. 1300.
pg 337 NOVEMBER 25, 1876.

NOVEM13ER 25, 18761 Icciaixtttic amino*. 337 frequently show their unfamiliarity with Nature by repeat-ing the old objections to any admission of breaks in the re-cord of the rocks, apparently unconscious that the pre-sent scope of geological knowledge is as limited, geographi-cally viewed, as the range of universal history was a century ago, or that it is simply absurd to argue as though what is ►own of the earth's history is the whole of that history, Even if we had, duly arranged in our cabinets, every fossil the world contains, we should still fall as far short of a con-nected history of life as our libraries do of a history of humanity. From the necessary conditions of the case, it is and must al ways be simply presumptuous to make sweeping asser-tions of what may or may not have been, in the absence of positive evidence. We can only assume that the unknown most probably conformed to the known in general character : that, if there is found in any region a sudden accession of vestiges of high civilization, it is more likely that a civi-lized people suddenly invaded that country and took posses-sion of it, as the whites have this country, than that a pe-culiar civilization came suddenly into existence by direct creation. And similarly, if we find a stratum of rock sud-denly (geologically speaking) filled with the remains of a higher form of life than the underlying strata showed, it is more reasonable to attribute the change to migrations, such as we have evidence of, than to creations, of which we have no evidence. And when all the evidence we have points to the evolution of higher types of civilization or of life from lower types: and since we know that, in our histories of earth and man, the unrecorded periods clearly exceed enor-mously in duration those of which we have even partial records; it is altogether more prudent to be modestly guided by the known than to give ourselves up, as the unscientific are prone to do, to wild imaginations and the traditions of those whose means of knowledge were demonstrably inferior to ours. THE STEREOSCOPE. We are indebted to the late Sir Charles Wheatstone for a series of investigations on binocular vision, which finally culminated in the invention of that now very popular little apparatus, the stereoscope. It was in 1823 that Wheatstone called attention to a fact until then hardly noticed, namely, that the perception of relief in objects is the result of the superposition of the images, one on each eye ; but these im-ages slightly differ from each other. The mind, guided by the experience of many years, receives in this way the im-pression of various distances ; and Wheatstone discovered that this impression may also be given to the mind by two pictures if each is drawn so as to correspond,respectively, to the image received by each eye. In order to prove this, Wheatstone invented the stereoscope. Considered from the standpoint of pure Science (apart from its practical applica-tion for amusement, instruction, and research, and the bi-nocular microscopes and telescopes that have grown out of it) this discovery of Wheatstone's is perhaps as interesting A recent application of the spectroscope, especially useful for the student of Science, consists in the reproduction of drawings of geometrical figures, illustrating the various forms used in the study of stereometry, such as the pro-jection of solids in descriptive geometry and spherical tri-gonometry, and especially in crystalography. In the latter science, it may be made especially useful, as, in this way, not only the crystals themselves, but also the forms result-ing from the interpenetration of two crystals, may be ex-plained better than can be done in any other way. The re-lation of various systems of crystalization, the transition of one form into another, the relation of the nucleus to ex-terior forms, the directions of cleavage, the position of axes of crystalization, the laws of double refraction, and various other more or less intricate subjects may thus be made sim-ple to the average understanding : and these studies may awaken some interest in this important subject, and sim-plify it to those who cannot afford to buy the expensive and bulky models of crystals. A number of stereoscopic pic-tures may thus be made equivalent to a collection of models costing as many dollars as the pictures cost cents. ARTIFICIAL BUTTER. There has been for some time past a prevalent impression that, if the manufacture of artificial butter has not died out, at least no product of this description is now industrial-ly made which has any standing in the market, or which cannot, by any one, be properly distinguished from the gen-uine article. It is true that the public, both in this country and more especially in England, has had placed before it in the newspapers more records of failures in artificial butter making than of the successful efforts therein; and these, to-gether with the popular prejudice which exists against the material, are sufficient, perhaps, to account for the general impression referred to. The facts, however, we are assured by competent authority, are altogether against any such con-clusion, for quite recently no less than fifty artificial butter factories were counted in this city; and large quantities of artificial butter are sold in the market by wholesale dealers, or are purchased direct from the manufactories by large re-tailers, and offered to the customer as genuine butter. There is, of course, a duplicity in this business which is re-prehensible; but if people cannot distinguish the made from the natural product, and if the former is, as reported by Professor Chandler, actually more healthful than the average cow butter sold, it would be difficult to prove any damages save to the moral sense to all, and to the over-qualmish pre-judices of a part, of the community. It will be seen furthermore that, the above being the case, the problem of succesfully producing the imitation product has been solved, and in that we may recognize an important step in scientific progress, which it is worth while to consider briefly in the light of previous efforts. As the successful process is based mainly on the invention of Hippolyte Mege, patented in this country in December 1873, the previous patents, obtained by Bradley in 1871, and by • " ,, Al __a. 1_1 T.1 stirred. After the scrap has settled, the clear yellow oil is drained off in cans, and left for from 12 to 24 hours in a room at 70° Fah. to granulate. The refined fat is now packed in cloth into small packages, about 8 inches long by 1+ inches thick by 4 inches wide, and these are placed on metal plates, and piled one above another in a press. Grad-ual pressure is applied, when the oil is driven out, and cakes of pure white stearin left. The oil, being cooled to 70° Fah., is next churned with sour milk, annatto. and soda, 100 lbs. of oil being used to 15 or 20 lbs. of milk, 3 ozs. of an-natto solution, and oz. of bicarbonate of soda. The mixture is agitated for ten or fifteen minutes, and then led into a tub of pounded ice, with which it is thoroughly mingled. This process completely removes the grain. After the ice melts, the solidified oil is crumbled, and 30 lbs. of it are in-troduced in a churn with 25 lbs. of churned sour milk. Here it takes up a percentage of the milk, as well as the but-ter flavor and odor. Lastly, the butter is worked and salted in the usual way, and is packed in firkins, etc., for the mar-ket. Hon. X. A. Willard, President of the New York State Dairymen's Association, an able butter expert, admits his surprise at the flavor, and declares the butter the best yet made. The cost of manufacture is about 13 cents a pound, the selling price 25 cents to wholesale dealers ; so that, so far as the saving is concerned, there is very little, over the cost of genuine butter. The economy, however, would doubt-less become manifest were the people willing to accept the material for what it is, and thus enable the industry to be-come established on a broader foundation. Dr. Mott's report on artificial butter, recently read before the Chemical Society of this city, contains complete details of his processes, together with a review of those previously patented, besides full chemical analyses, complete estimates, and plans for a factory capable of producing 500 lbs. of but-- ter daily, and drawings of apparatus, etc. This valuable pa-per, too lengthy for these columns, appears in full in the SCIENTIFIC AMERICAN SUPPLEMENT, Nos. 48 and 49, cur-rent volume. THE SALT BLUFFS OP VIRGIN RIVER, NEVAIA. The mineral wealth of Nevada is by no means confined, as many may suppose, to Big Bonanzas and similar stores of precious metal hid within its seemingly barren moun-tains. In many places its sterile plains—the beds of recent-ly evaporated seas—are underlaid with extensive strata of cruder though possibly not less important commodities, among which common salt is certainly not the least valu-able. Perhaps the most important of the formations of this character are the vast deposits of rock salt along the valley of the Rio Virgin, in the southeastern corner of the State. Their discovery is quite recent. Lieutenant Wheeler, in charge of the survey of the region west of the 100th meri-dian, first visited their neighborhood in 1869, and again two years later, at which time the only indication of their pres can(..' n nintlarca fn it Arn /1..11 n r•Tivir,ioa tmr‘Al (((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((( THE SCIENTIFIC AMERICAN SUPPLEMENT. Vol. II., No. 48. For the Week ending November 25 9 1876. TABLE OF CONTENTS. I. THE INTERNATIONAL EXHIBITION OF 1876.

With 12 illustrations.—Exhibits of Molding and Founding ; Apparatus for Sweeping Prismatic and Circular Patterns, Ring and Polygonal Figures; Ornamental Fig-ures; Swept Patterns of Various Shades; Apparatus for Sweeping Gear Wheel Patterns; for Forming and Adjusting the Teeth; for Soft Metal Patterns; for Cast Iron Beams .—Exhibits of Rock Drills, The Burleigh Drill II. ENG(NEERING AND MECHANICS.—The Great Suspension Bridge between New York and Brooklyn, with 4 illustrations.—Description of the Mode of Making and Laying the Cables, the Cradles, and Tempo-rary Foot Bridge.—Phosphor _Bronze, a valuable paper, showing its Uses, with Tables of its Comparative Strength.—The Use of the Mag-netic Needle in Searching for Iron Ore, by Professor J. C. SMOCK, Showing the Magnetism of Mineral Rocks, the Styles of Compass best suited for Exploration of the Ground Surface, Methods of Use, Manner of Surveying. etc. A valuable and interesting paper.--Compass Cor-rections of Iron Ships, by SIR WILLIAM TllomsoN.—Report of the Western Union. Telegraph Company ; Progress of Pneumatic Tubes in New York.—The Copper Deposits of America, by T. STERRY HUNT. — The Process of Hydraulic Mining at Dutch f lat.—Spring Motors, with 5 figures.—Plan for Street Car Propelled by Rubber Springs, 2 figures.—Combined Spring Motor,by C.J.SCHUMACHER, 3 figures.—Natural Gas.— Water Railways, with 4 illustrations.—The Proposed Road Locomotive, 330 feet long, 125 feet high, intended to run on the bottom of the En-glish Channel,between _France and England,2 figures.—The Water Rail-way now in operation at St. Malo, France, 2 engravings.—The New 100 Tun Gun made for the Italian Government, 1 engraving.—Trials of the New 81-tun Gun, England. How the 81-tun Gun was Made, with 8 fig-ures.—Oils and Fat Destructive to Iron.—Centroids and their Applica-tion to Mechanical Problems.—A Steam Lamp.—Experiments on the Turning of Screw Steamers, by Professor OSBORNE REYNOLDS.—New Standards of Weights and Measures, by Professor HENNESSY. III. TECHNOLOGY.—Manufacture of Artificial Butter, by Henry A. Mott, Jr., E. M. Ph. D. of New York, with six engravings. Being a full De-scription of the Method of Manufacture, Apparatus, Cost and Profits• A full and valuable paper, clearly explaining the entire process.—Aciion of Alcohol on the Brain.—A New Voltaic Cell, paper read before the British Association, by C. H. W. BRIGGS.—Professor Bell's Speaking Telegraph. Specimens of Conversation as Carried on Over Telegraph Wires.—Photographs upon an Enamel or Porcelain. Newton's New Process for Photo-Emulsion Plates.—How to Use Photographic Back-'rounds, by L. W. SEAVEY, of New York, with fourteen illustrations. Professor Seavey is the acknowledged master of the art of producing and using photo-backgrounds; and in this paper he fully explains the methods adapted for the production of the best practical effects in pho-tographic portraiture. Every artist should read this valuable paper. IV. LESSONS IN MECHANICAL DRAWING, No. 28. By Professor C. W. MACCORD, with 10 illustrations. The Scientific American Supplement is a distinctive publication issued weekly ; every number contains 16 oc-tavo pages, with handsome cover, uniform in size with SCIENTIFIC AMERI-CAN. Terms of subscription for SUPPLEMENT, $5.00 a year, postage paid, to subscribers. Single copies, 10 cents. Sold by all news dealers through-out the country. To SCIENTIFIC AMERICAN SUBSCRIBERS WHO WISH TO TAKE THE SUPPLE-MENT.—A subscriber to the SCIENTIFIC AMERICAN may change at any time uo the SUPPLEMENT, or may have both papers sent to him, by remitting to us the difference between the amount already paid for the SCIENTIFIC AMERI-CAN and the SUPPLEMENT prices above mentioned. Remit by postal order. Address COMBINED RATES.—The SCIENTIFIC AMERICAN and SCIENTIFIC AMER-ICAN SUPPLEMENT will be sent together for one year, postage free to sub-Scribers, on receipt of $7.00. All tne numbers 01 tilt SUPPLEMENT from its commencement, January 1, 1876, can be supplied ; subscriptions date with No. 1 unless otherwise or-dered.

Gradually historical research and archaeological investiga-tion came in to discover and imperfectly bridge over enor-mous gaps in the history once thought complete; highly im-portant events were found to have been lost track of; during long periods of time no records had been kept, and of records carefully made only disconnected fragments have survived ; unmentioned or falsely mentioned empires were found to have flourished side by side with those which had professed to be not only the people but the only people of their day, while others a little further off wore utterly unknown. Splendid civilizations, lasting many centuries, had contribu-ted nothing to the written chronicles of the nations whose records remained ; and others which had apparently burst in full panoply upon the gaze of an astonished world, were found to have had their beginning in barbarism, and to have slowly risen to the lofty stage at which history had formerly found them. Still more fatal to the ancient view of universal history were the discoveries that, at the generally accepted date of man's beginning, Egypt was in her decline, the grandeur of her civilization having, reached its culmination before Satan talked with Eve in the garden, and that other parts of the world which, had been accounted historically blank could show, like China and Peru, the remains of civilization cer-tainly as ancient as that of Egypt. Then geology came forward to show that the six thousand years of Hebrew chronology, or the doubly extended chro-nology of Egypt, covered but a minute fraction of the time since man made his first recognized appearance on our globe, and that all we know of human history is as nothing com-pared with the unrecorded ages of which we only know that man existed. Evidence of the gaps in the story of human-ity, gaps of enormous duration, are indeed overwhelming. Evidence of what man was doing during those ages is for the most part nil. It is possible, however, to bridge over some of those periods by inferences which cannot be consid-ered wholly illegitimate. We know that, back of every civi-lization which has been critically studied (no matter how ab-ruptly that civilization may have first seemed to come upon the stage of history),there have been found evidences of low-er and still lower culture. In some cases it has been possible to trace the successive steps of progress almost continuously from barbarism upward, and everywhere the drift of evi-dence touching early races is such as to justify the convic-tion that civilization has always been a product of human effort and time. Even when the antecedents of a civiliza-tion are lost entirely, we still know enough of human devel-opment not to believe that the nation began when and as it first appeared on the stage of history. All this is now common place enough, we are well aware; and it would be unworthy of serious rehearsal here were it not for the instructive parallel which may be drawn between it and the historical interpretation of the equally intermit-tent and fragmentary records of geology, touching which there is still a great deal of misunderstanding. In the early days of geological observation, men proceeded just as they had done in the case of human history. It was assumed that the rocks contained a divinely appointed re- 777777777777777 MUNN & CO., PUBLISHERS, 37 Park Now, New York. 1111r Single copies of any desired number of the SUPPLEMENT sent DO any address on receipt of 10 cents

. million people were engaged in a bitter and terrible inter necine war. Now, great national gatherings have taken place day after day, unmarred by a word of sectional strife or ill feeling. For three years the nation has been suffering under a shrinkage of values and a financial stress which has brought ruin to thousands, and of which no one has escaped the evil effects. Yet despite all the privations and suffering incident thereto, a vast national enterprise has not only been successfully carried through, but has included such a representation of the fruits of American industry and genius as has never before been seen. While we cannot yet point to special results due to the Centennial, we may at least be assured that it has imparted to our people a valuable and healthy appreciation of the " goodness which lieth abroad." Its tendency has been to break down that bulwark of intolerance and self-sufficiency which Brother Jonathan too often deems in accordance with his independent notions of self-sovereignty, and which has caused him to depreciate the productions of older na-tions. On the other hand, it has opened the eyes o f the world to the fact that we are ready to compete for prece-dence in the trade in certain products, hitherto monopolized abroad, notably our steel, our porcelain, our cotton goods, and our silks. We have also learned to compare our own work with that done in Europe; and having found where we are excelled as well as where we excel, we have stored up a stock of ideas, sure to bear rich fruit in the future. In these ideas and thoughts suggested, in extended com-merce due to the closer intercourse with, and hence better knowledge attained of, other nations, in the consequent im-petus to our industries and educational systems, and in a broader cosmopolitan spirit diffused over the whole country, do we look for the best results yet to be gained from the Centennial Exposition.

INTERMITTENT RECORDS AND THEIR INTERPRETATION
A few years ago, men wrote universal history with the utmost precision and confidence, as though the doings and developments of humanity, during all ages and in every part of the world, were perfectly known. The threads of human history, so far as then possessed, plainly converged toward a little tract of country east of the Mediterranean Sea; and believing that the Scriptures contained a divinely inspired account of man's origin there, men not unreasona-bly inferred that all the world outside their knowledge was actually or practically blank. But for the past half century, intelligent people have ceased to entertain that view, except with great and various modifications, determined by a more or less honest desire to maintain the integrity of the scrip-tural record. As soon as the matter began to be critically investigated, it became very clear that, so far from being complete and continuous, the chronicles which had been woven so often into exhaustive histories, were disconnected and fragmentary, extremely limited in scope, and wretched-ly deficient every way. Even when fullest, they gave but scanty information of the daily lives of the people, the move-ments of nations, the rise of empires, the progress of inven-tion and discovery, indeed of everything now considered most valuable and important, historically considered.

opment not to believe that the nation began when and as it first appeared on the stage of history. All this is no w common place enough, we are well aware; and it would be unworthy of serious rehearsal here were it not for the instructive parallel which may be drawn between it and the historical interpretation of the equally intermit-tent and fragmentary records of geology, touching which there is still a great deal of misunderstanding. In the early days of geological observation, men proceeded just as they had done in the case of human history. It was assumed that the rocks contained a divinely appointed re-cord of the earth's history, from which men could gather an exhaustive knowledge of the whole earth's experience. The strata of England and Western Europe were studied with great enthusiasm; their relative ages were determined, and their fossil remains were arranged according to the assumed order of their creation, with more or less forcing to make them tally with the Mosaic days. Everything seemed straightfor-ward and easy. If fish appeared in great numbers in one stratum, it was because they were created then and there ; if monstrous lizards swarmed suddenly in another, it was be-cause a new chapter had been begun in the geologic history; and so on to the minutest detail. But as knowledge increased by the study of outlying stra-ta, grave doubts began to arise with regard to the complete-ness of the supposed "perfect.' record and the correctness of previous interpretations. The times of "first" beginnings had to be pushed back again and again. Formations supposed to have succeeded each other immediately were found else-where to be separated by deposits of vast thickness, requir-ing enormous periods of time for their deposition. Creatures supposed to have come suddenly into being in one age were found to have existed at periods immensely more ancient. Gaps were discovered where none lead been suspected; broad distinctions of age and formation were ruthlessly wiped out; and as the work went on, it became more and more apparent that the classifications and chronologic schemes, which had been so confidently adopted, were largely misleading or meaningless. To those who studied geology in books, the completeness and continuity of the geologic record remained undoubted; to those, however, who were engaged in the study of the record itself, its intermittent and fragmentary nature was most apparent. It was seen that only under rare and exceptionally favorable conditions was it possible that any record of life could be made. It was only under still more exceptional conditions that the record, if made, could be preserved. And when the limited scope of geological investigation was taken into the account, the absurdity, of the early deductions considered as comprehensive and ex-haustive, became ludicrously plain. Yet when Mr. Darwin appealed to the imperfection of the geologic record, closet geologists everywhere raised a great laugh of derision, as thought he had invented the plea to cover the weakness of his case. Public opinion on this point had indeed to under-go the same course of instruction and enlightenment that we have noticed in connection with the history of man, a course which it has not yet by any means completed. Even men who consider themselves competent to discuss publicly the deeper problems of geology, evolution, and so on, not un- close of 336 Centennial notes 345 Centennial revives business, the 341 Centennial, the closing of the 345 Centennial, the Corliss engine" 340 Pottery display, the French Practical mechanism—No. 15" Putty, removing Railways and locomotives. Records, intermittent, etc 3,15 341 346 339 336 Chairs, common sense 342 Safe, fireproof and burglarproof.*338 Chloroform in sleep 338 Salt bluffs of Nevada 337 Collodion, removing (14) 317 Scientific apparatus, French 345 Condenser, duction coil (17).... 347 Silver-plating solution (13). 347 Counter ge'a or lathes* Electrotypi insects, etc is; 342 341 Soapstone, dissolving (19) Stars, the twinkling of the 347 343 Enameled cooking vessels 338 Stereoscope, the '337 Encyclopaedia, Appleton's 343 Sun's inotion,the,and the weather 340 Engine, the Centennial Corliss 340 Tapestry, French 345 Evolution, thoughts on 345 Time drop for clocks" 338 Fay & Co.'s exhibit* 335, 344 Tortoiseshell scraps (10) 347 Fertilizers, potash and bone (9) .. 347 Wagon wheel, weight on a (1) 347 _Fire, in case of 338 Water supply for towns 341 Fish culture 145 Weather and the sun's motion.... 340 Fish, twin 345 Weight at poles and equator (6) .. 347 Fox fire (11) 347 Weights and measures 345 Gaslights, the inventor of 341 Wire rope, origin of 341 Glass and lead (18) 347 Woodworking machinery* ...335, 344 Glass plates, large 345 Wool and hair, detection of 346

MUNN & CO., Editors and Proprietors. PUBLISHED WKLY AT NO. 87 PARK ROW, NEW YORK.
0. D. MUNN. A. E. BEACH.

TERMS FOR THE SCIENTIFIC AMERICAN. One copy, one year. postage included $3 20 One cony, six months, postage included 1 60 Club Rates. Ten copies, one year, each $2 '70, postage included $27 00 Over ten copies, same rate each, postage included 2 70 rir The postage is payable in advance by the publishers, and the sub-scriber then receives the paper free of charge. NOTE.—Persons subscribing will please to give their full names, and Post Office and State address, plainly written. In case of changing residence state former address, as well as give the new one. No changes can be made unless the former address is given. Scientific American Supplement. A distinct paper from the SCIENTIFIC AMERICAN, but of the same size and published simultaneously with the regular edition. One year by mail TERMS. $5 00 SCIENTIFIC AMERICAN and SUPPLEMENT, to one address 7 00 Single Copies 10 The safest way to remit is by draft, postal order, or registered letter. Address MITNN & Co., 37 Park Row, N. Y. tar- Subscriptions received and single copies of either paper sold by all the news agents. VOLUME XXXV., No. 22, [NEw SERIES.] Thirty-ft/rat Yeavr. NEW YORK, SATURDAY, NOVEMBER 25, 1876. Contents. (Illustrated articles are marked with an asterisk.)

Academy of Sciences, New York 345 Air and mine ventilation 343 Annotta. 343 Answers to correspondents 347 Bank clerks Batteries, plates for (15) Bevel, improved. Bixa orellana* Boats, engines, etc. (7) Boiler, setting a (3, 5) Boiler, water from a (16) Brass, malleable (20) Brass pans, cleaning Burns, cure for 347 338 343 347 347 347 347 341 337 Business and personal 347 Business, stick to a legitimate 341 Butter, artificial 337 Canal, the Bude, England 810 Castor oil plant, the* 343 Centennial exhibit, Fay& Co ' s."335,344 Centennial exhibition, close of 336 Centennial notes 345 Centennial revives business, the 341 Centennial, the closing of the 345 Centennial, the Corliss engine 340 Chairs, common sense 342 Chloroform in sleep 338 Collodion, removing (14) 317 Condenser, induction coil (17) 347 Counter gear for lathes. '342 Electrotyping insects, etc 341 Enameled cooking vessels 338 Encycloptedia, Appleton's 343 Engine, the Centennial Corliss 140 Evolution, thoughts on 345 Fay & Co.'s exhibit. 335, 344 Fertilizers, potash and bone (9) 347 Fire, in case of 338 Fish culture 445 irs Grindstones, speed of (3) 347 Gum copal, dissolving 346 Hospital in a crater, a 343 Ice, formation of (7) 347 Ice water head dress, a 342 Iodide of potassium crystals (8) 347 irrigator, a new* 338 Launches, speed of (4) 347 Leveling without a theodolite (2) 347 Locomotive, rapid transit" 342 Locomotives and railways. 339 Lyall loom, the awards to the 345 Microscopic detection 346 Mine ventilation, facts about 343 Oils, the adulteration of 346 Oxygen, our supply of 345 Patents, American and foreign 346 Patents, official list of 347 Planet Vulcan, the supposed 340 Plant, a dangerous 342 Pottery display, the French 345 Practical mechanism—No. 15* 341 Putty, removing 346 Railways and locomotives. 339 Records, intermittent, etc 336 Safe, fireproof and burglarproof ..338 Salt bluffs of Nevada 337 scientific apparatus, French 345 Silver-plating solution (13). 347 Soapstone, dissolving (19) 347 Stars, the twinkling of the 343 Stereoscope, the 337 Sun's inotion,the,and the weather 340 Tapestry, French 345 Time drop for clocks. 338 Tortoiseshell scraps (10) 347 Wagon wheel, weight on a (1) 347 Water supply for towns 341 Weather and the sun's motion 340 wolcylit ,it nrIlou and J.ntintnr (Al 341

20834 SCIENTIFIC AMERICAN SUPPLEMENT, No. 1300.
pg 336 NOVEMBER 25, 1876.

THE SCIENTIFIC AMERICAN SUPPLEMENT. Vol. II., No. 48. For the Week ending November 2591876. TABLE OF CONTENTS. I. THE INTERNATIONAL EXHIBITION OF 1876.

With 12 illustrations.—Exhibits of Molding and Founding ; Apparatus for Sweeping Prismatic and Circular Patterns, Ring and Polygonal Figures; Ornamental Fig-ures; Swept Patterns of Various Shades; Apparatus for Sweeping Gear Wheel Patterns; for Forming and Adjusting the Teeth; for Soft Metal Patterns; for Cast Iron Beams .—Exhibits of Rock Drills, The Burleigh Drill II. ENG(NEERING AND MECHANICS.—The Great Suspension Bridge between New York and Brooklyn, with 4 illustrations.—Description of the Mode of Making and Laying the Cables, the Cradles, and Tempo-rary Foot Bridge.—Phosphor _Bronze, a valuable paper, showing its Uses, with Tables of its Comparative Strength.—The Use of the Mag-netic Needle in Searching for Iron Ore, by Professor J. C. SMOCK, Showing the Magnetism of Mineral Rocks, the Styles of Compass best suited for Exploration of the Ground Surface, Methods of Use, Manner of Surveying. etc. A valuable and interesting paper.--Compass Cor-rections of Iron Ships, by SIR WILLIAM TllomsoN.—Report of the Western Union. Telegraph Company ; Progress of Pneumatic Tubes in New York.—The Copper Deposits of America, by T. STERRY HUNT. — The Process of Hydraulic Mining at Dutch f lat.—Spring Motors, with 5 figures.—Plan for Street Car Propelled by Rubber Springs, 2 figures.—Combined Spring Motor,by C.J.SCHUMACHER, 3 figures.—Natural Gas.— Water Railways, with 4 illustrations.—The Proposed Road Locomotive, 330 feet long, 125 feet high, intended to run on the bottom of the En-glish Channel,between _France and England,2 figures.—The Water Rail-way now in operation at St. Malo, France, 2 engravings.—The New 100 Tun Gun made for the Italian Government, 1 engraving.—Trials of the New 81-tun Gun, England. How the 81-tun Gun was Made, with 8 fig-ures.—Oils and Fat Destructive to Iron.—Centroids and their Applica-tion to Mechanical Problems.—A Steam Lamp.—Experiments on the Turning of Screw Steamers, by Professor OSBORNE REYNOLDS.—New Standards of Weights and Measures, by Professor HENNESSY. III. TECHNOLOGY.—Manufacture of Artificial Butter, by Henry A. Mott, Jr., E. M. Ph. D. of New York, with six engravings. Being a full De-scription of the Method of Manufacture, Apparatus, Cost and Profits• A full and valuable paper, clearly explaining the entire process.—Aciion of Alcohol on the Brain.—A New Voltaic Cell, paper read before the British Association, by C. H. W. BRIGGS.—Professor Bell's Speaking Telegraph. Specimens of Conversation as Carried on Over Telegraph Wires.—Photographs upon an Enamel or Porcelain. Newton's New Process for Photo-Emulsion Plates.—How to Use Photographic Back-'rounds, by L. W. SEAVEY, of New York, with fourteen illustrations. Professor Seavey is the acknowledged master of the art of producing and using photo-backgrounds; and in this paper he fully explains the methods adapted for the production of the best practical effects in pho-tographic portraiture. Every artist should read this valuable paper. IV. LESSONS IN MECHANICAL DRAWING, No. 28. By Professor C. W. MACCORD, with 10 illustrations. The Scientific American Supplement is a distinctive publication issued weekly ; every number contains 16 oc-tavo pages, with handsome cover, uniform in size with SCIENTIFIC AMERI-CAN. Terms of subscription for SUPPLEMENT, $5.00 a year, postage paid, to subscribers. Single copies, 10 cents. Sold by all news dealers through-out the country. To SCIENTIFIC AMERICAN SUBSCRIBERS WHO WISH TO TAKE THE SUPPLE-MENT.—A subscriber to the SCIENTIFIC AMERICAN may change at any time uo the SUPPLEMENT, or may have both papers sent to him, by remitting to us the difference between the amount already paid for the SCIENTIFIC AMERI-CAN and the SUPPLEMENT prices above mentioned. Remit by postal order. Address COMBINED RATES.—The SCIENTIFIC AMERICAN and SCIENTIFIC AMER-ICAN SUPPLEMENT will be sent together for one year, postage free to sub-Scribers, on receipt of $7.00. All tne numbers 01 tilt SUPPLEMENT from its commencement, January 1, 1876, can be supplied ; subscriptions date with No. 1 unless otherwise or-dered.

Academy of Sciences, New York 345 Air and mine ventilation 343 Annotta. 343 Answers to correspondents 347 Bank clerks Batteries, plates for (15) Bevel, improved. Bixa orellana* Boats, engines, etc. (7) Boiler, setting a (3, 5) Boiler, water from a (16) Brass, malleable (20) Brass pans, cleaning Burns, cure for 347 338 343 347 347 347 347 341 337 Business and personal 347 Business, stick to a legitimate 341 Butter, artificial 337 Canal, the Bude, England 810 Castor oil plant, the* 343 Centennial exhibit, Fay& Co ' s."335,344 Centennial exhibition, close of 336 Centennial notes 345 Centennial revives business, the 341 Centennial, the closing of the 345 Centennial, the Corliss engine 340 Chairs, common sense 342 Chloroform in sleep 338 Collodion, removing (14) 317 Condenser, induction coil (17) 347 Counter gear for lathes. '342 Electrotyping insects, etc 341 Enameled cooking vessels 338 Encycloptedia, Appleton's 343 Engine, the Centennial Corliss 140 Evolution, thoughts on 345 Fay & Co.'s exhibit. 335, 344 Fertilizers, potash and bone (9) 347 Fire, in case of 338 Fish culture 445 irs Grindstones, speed of (3) 347 Gum copal, dissolving 346 Hospital in a crater, a 343 Ice, formation of (7) 347 Ice water head dress, a 342 Iodide of potassium crystals (8) 347 irrigator, a new* 338 Launches, speed of (4) 347 Leveling without a theodolite (2) 347 Locomotive, rapid transit" 342 Locomotives and railways. 339 Lyall loom, the awards to the 345 Microscopic detection 346 Mine ventilation, facts about 343 Oils, the adulteration of 346 Oxygen, our supply of 345 Patents, American and foreign 346 Patents, official list of 347 Planet Vulcan, the supposed 340 Plant, a dangerous 342 Pottery display, the French 345 Practical mechanism—No. 15* 341 Putty, removing 346 Railways and locomotives. 339 Records, intermittent, etc 336 Safe, fireproof and burglarproof ..338 Salt bluffs of Nevada 337 scientific apparatus, French 345 Silver-plating solution (13). 347 Soapstone, dissolving (19) 347 Stars, the twinkling of the 343 Stereoscope, the 337 Sun's inotion,the,and the weather 340 Tapestry, French 345 Time drop for clocks. 338 Tortoiseshell scraps (10) 347 Wagon wheel, weight on a (1) 347 Water supply for towns 341 Weather and the sun's motion 340 wolcylit ,it nrIlou and J.ntintnr (Al 341

close of 336 Centennial notes 345 Centennial revives business, the 341 Centennial, the closing of the 345 Centennial, the Corliss engine" 340 Pottery display, the French Practical mechanism—No. 15" Putty, removing Railways and locomotives. Records, intermittent, etc 3,15 341 346 339 336 Chairs, common sense 342 Safe, fireproof and burglarproof.*338 Chloroform in sleep 338 Salt bluffs of Nevada 337 Collodion, removing (14) 317 Scientific apparatus, French 345 Condenser, duction coil (17).... 347 Silver-plating solution (13). 347 Counter ge'a or lathes* Electrotypi insects, etc is; 342 341 Soapstone, dissolving (19) Stars, the twinkling of the 347 343 Enameled cooking vessels 338 Stereoscope, the '337 Encyclopaedia, Appleton's 343 Sun's inotion,the,and the weather 340 Engine, the Centennial Corliss 340 Tapestry, French 345 Evolution, thoughts on 345 Time drop for clocks" 338 Fay & Co.'s exhibit* 335, 344 Tortoiseshell scraps (10) 347 Fertilizers, potash and bone (9) .. 347 Wagon wheel, weight on a (1) 347 _Fire, in case of 338 Water supply for towns 341 Fish culture 145 Weather and the sun's motion.... 340 Fish, twin 345 Weight at poles and equator (6) .. 347 Fox fire (11) 347 Weights and measures 345 Gaslights, the inventor of 341 Wire rope, origin of 341 Glass and lead (18) 347 Woodworking machinery* ...335, 344 Glass plates, large 345 Wool and hair, detection of 346

(((((((((((((((((((((((((((((((((((((((( the experience of many years, receives in tills way tile im-pression of various distances ; and Wheatstone discovered that this impression may also be given to the mind by two pictures if each is drawn so as to cerrespond,respectively, to the image received by each eye. In order to prove this, Wheatstone invented the stereoscope. Considered from the standpoint of pure Science (apart from its practical applica-tion for amusement, instruction, and research, and the bi-nocular microscopes and telescopes that have grown out of it) this discovery of Wheatstone's is perhaps as interesting as any other invention of recent date, not excepting the ka-leidoscope, the telephone, the pseudoscope, and the revol-ving mirror for measuring the velocity of light, etc. Sir David Brewster, who was erroneously supposed by many to have invented the stereoscope, used often, while insisting on the importance of this new conquest in physical science, to describe this instrument unhesitatingly as the most re markable gift with which the study of binocular vision had been enriched. The first stereoscope by which Wheatstone demonstrated his discovery was a reflecting stereoscope. Two vertical mirrors were placed so as to make, respectively, an angle of 45' with the axes of the eyes, and in such a position as to reflect the rays coming from the right and left into the eyes, the mirrors being joined at a middle point between the axes. Two perspective drawings, correctly made, so as to correspond with the image which the real object would make in each eye, were then so placed, at the right and left, as to cause these images in the mirrors to coincide in the act of vision, and the illusion was perfect. Wheatstone found later that he could dispense with the mirrors and simplify the apparatus by using two prisms, to which he had lenses attached so as to magnify the drawings. Brewster finally had prismatic lenses made, joined by their thinnest edges, by which small drawings, placed at the distance of, say, three inches, could be made to coincide for the vision. It should, however, be mentioned that Duboscq, of Paris, was the first to give to the stereoscope the simple practical form in which it is now seen in the trade ; but its popularity did not become established until photography came to its aid, to make binocular pictures perfect in all their details. It was at the first universal exposition,in London, in 1851, that Duboscq exhibited a stereoscope, and then for the first time the instrument became noticed by the public, although, it had been known to scientists for 13 years, during which' time Dr. Carpenter and others had continually, in lectures on physical sciences, exhibited the instrument and demon-strated the principles of Wheatstone's discovery. Accord-ing to the statements of one manufacturer of optical in-struments, a long time elapsed before the people began to appreciate the beauties of the stereoscope ; and_for several years no sales of any importance could be made. But at last its merits were realized, and suddenly a large demand sprung up. The stereoscope soon became in fashion ; and the manufacture of the different forms of the instrument (varying in price from 50 cents to $100), the grinding of the prismatic lenses, and the production of the photographic pictures (on paper and on glass) have now become an impor-tant branch of business, in which thousands of artists and workmen are occupied. save to the moral sense to all, and to the over-qualmish pre-judices of a part, of the community. It will be seen furthermore that, the above being the case, the problem of succesfully producing the imitation product has been solved, and in that we may recognize an important step in scientific progress, which it is worth while to consider briefly in the light of previous efforts. As the successful process is based mainly on the invention of Hippolyte Mege, patented in this country in December 1873, the previous patents, obtained by Bradley in 1871, and by Peyrouse in the same year, as well as that taken out by Paraf in April, 1873 (which last is charged to be a piracy of Mege's ideas) need not be referred to. The best points of Mege's invention are found combined in the reissue of his patents, dated May 12, 1874, and among them these two essential and important operations, namely, the extracsion of the oil from the fat, at a low temperature, and the conversion of the oil, by churning with milk, into butter. The caul fat, being washed, is hashed, melted in a water bath at 125° Fah., and, after becoming separated from the membrane, is allowed to solidify. It is then pressed, and the oil treated in different ways according as the resulting product is intended for immediate or future use. It will suffice here to say that the product thus obtained has a grain, and seemingly has no resemblance to genuine butter save in color. With refer-ence to the many other patents issued since the date of Mege's, it may be said that, as a rule, the common defects, of grain, lack of savor, and inferior keeping quality, are pre-sent in all; and the products may more fairly be described as chemically prepared tallow than as butter. The above statements are made on the authority of Dr. Henry A. Mott, E. M., a promising young chemist of this city, who for some years back has been engaged in investi-gating the subject we are here examining. His researches have included the actual manufacture and testing of the va-rious compounds patented ; and their result is found in the present, or " true," as he terms it, process for producing ar-tificial butter. To Dr. Mott belongs the credit of this dis-covery, although the ownership of his process is in the hands of others; and, its salient feature is that he produces, not tallow disguised as butter, but butter itself. This will be seen at once from the fact that chemical analysis of cream butter gives water 12.29, and solids 87.71 parts per 100: of artificial butter, water 12.005, solids 87'995. The amount of casein in the artificial product, the detailed analysis shows to be a little higher than in the natural butter (0.745 to 0.19) but not sufficient to make any difference. Compar-ing the fats proves that there is a very small amount of butyrin in the artificial product, and herein lies the chief disparity : which amounts to an absolute virtue, because, while sufficient butyrin exists to afford the necessary odor and flavor to the artificial product, there is not enough con tamed to render the butter rancid by decomposition. Dr. Mott's process of manufacture is as follows : The fat, after being weighed, is thoroughly and repeatedly washed in tepid and cold water. It is then disintegrated in a meat hasher, and forced through a fine sieve, Next, it is placed in the melting tank, which is surrounded by water at 116° Fah., and there kept until the temperature of the fat reaches 124° Fah. During this process the material is constantly among which common salt is certainly not the least valu-able. Perhaps the most important of the formations of this character are the vast deposits of rock salt along the valley of the Rio Virgin, in the southeastern corner of the State. Their discovery is quite recent. Lieutenant Wheeler, in charge of the survey of the region west of the 100th meri-dian, first visited their neighborhood in 1869, and again two years later, at which time the only indication of their pres ence appears to have been a curious natural well, which Mr. G. K. Gilbert describes and figured in his report on the ge-ology of those parts. It lies near the confluence of the Rio Virgin and the Colorado, in a smooth gravelly plain sloping gradually toward the latter, and presents a round, crater-like opening nearly three hundred feet across at the top. The sides are of unconsolidated detritus horizontally bedded, the upper thirty-five feet being of half-sorted gravel and sand, and the lower fifteen feet of saline sand showing a slight efflorescence. At fifty feet below the land surface is a water level about a hundred and twenty feet across, and below the water the slope of the bottom can be seen contin-uous with the bank for fifteen or twenty feet. The water is too salt for drinking. There is no sign that the well ever overflowed, the water is not thermal, and no marks of gey-ser action are to be seen. Mr. Gilbert suggests that the well might have been opened by the solution of a salt de posit, which is extremely probable in view of the vast ex:- tension of saline strata along the river valley. A correspondent of the San Francisco Chronicle, who lately made a special visit to the salt quarries now being opened up at various points from six to twenty miles above the Colorado, reports that the rock salt occurs in " moun-tains," and is quarried like marble or granite. The salt mountains begin about six miles from the mouth of the Rio Virgin and extend along its valley a distance of thirty miles. For the first six miles or so, the salt rock appears like coin= mon coarse gray granite, and is said to contain 92 per cent of pure salt. The quarries here lie along the east side of the river and within half a mile of the river bank. On the western side, twenty miles up, the salt is as white as snow on the surface but beautifully transparent within. The blocks of salt thrown out by blasting look like cakes of clear ice, so crys-talline that fine print can be read through several inches of it. The Rio Virgin is a muddy turbulent stream about a hun-dred feet wide and very shallow. Where it joins the Colo-rado,the latter is perhaps seven hundred and fifty feet wide and from ten to fifty feet deep at low water. The head of navigation is at Collville, twenty-five miles below, but small barges of a few tuns burden are towed up to the mouth of the Virgin for cargoes of salt for supplying the mines of El Dorado cation and elsewhere. The Virgin joins the Colora-do at a point six hundred miles above its mouth, and about fifty miles below the outlet of the Grand Callon. The re-gion about the salt mines is altogether barren and desolate. PAINTING the surface with ink soon relieves the pain of a small superficial burn.