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This hasty resumé of some of the leading facts in the growth of a branch of science, the history of which practically begins with that of the Institute, to which the occasion more naturally invited than to a display of its achievements, would find its highest justification in the enumeration of its applications. But a very few must suffice. In scientific investigation the eye has been replaced in so many cases by the camera, for observation as well as record, that we begin to inquire what is left for visual observation. This is not for the relief of the eye, but because the photographic plate has so much wider range in time and space. It is capable of observing the instantaneous, and yet of looking without wearying, but with cumulative effect by the hour to catch phenomena to which the eye, with its best aids, is hopelessly blind. It has even been said by an eminent astronomer, that it has added to observing power as much as the invention of the telescope. It has, in fact, revolutionized astronomy. Beginning with the Moon, with which perhaps least has been accomplished, total eclipses of the Sun have yielded up long desired information, otherwise unattainable, so that they, by comparison, approach the character of worked-out fields. Automatic daily observations of the solar surface, with the details of its spots, promise data for determining effects upon terrestrial climate. Nebulæ have been discovered, their form, details and conditions revealed, and fainter extensions, vaster than could be conceived, added. Comets have exhibited wonderful transformations, distortions and internal movements utterly undiscoverable by the best telescopes alone. Asteroids so numerous leave the record of their existence in trails upon the plates that, as has been said by Professor Barnard, they are turned adrift again unless they show some striking peculiarity of orbit. Meteors record their paths on which rests the expectation of precise determination of the radiant. Combined with the spectroscope, binaries of shortest periods are detected, variable stars not only discovered, but classified. The surmises of mathematicians in regard to Saturn's rings are confirmed. Runaway stars are caught. The Parisian astronomer that could

Extract from an address. Oct. 2, 1899, on the 75th anniversary of the Franklin Institute, Philadelphia, Pa.

not catch the satellite of Neptune with his telescope, could see it fixed on his photographic plate.

Photography and microscope, too, have gone hand-in hand with a more intimate sympathy even than that between the camera and telescope. Among the earliest amateurs of highest character was a large percentage of experts with the microscope. It was in the decade following the founding of the Institute that the microscope began to assume something of its present character as an instrument of delicacy and precision. In 1831, the factory of Ross was established, and under the stimulus and coöperation of such men as Herschel, Airy, Powell, and more especially Lister, improvements in the optics and mechanics of the microscope were rapidly made, so that at the discovery of photography, microscopy had an entirely modern aspect, and it recognized at once a new ally. Dr. Draper immediately took microdaguerreotypes. From this time the improvements in optical appliances urgently demanded by the microscopist were ably seconded by the photographer, and both combined were largely instrumental in occasioning the marked progress in practical optics, which, in turn, reacted to advance photography and microscopy. Even in the days of slow wetcollodion good work was done with the microscope, and even stereo-photo-micrographs were taken by Professor Rood. The rapid dry-plate, sensitive to all or any desired colors, has nowhere contributed more to the advance of photographic practice than with the microscope. It has become to it only less the observing and recording eye than to the telescope. The intimate connection between the microscope and the camera is also well exemplified in the Institute, where the gifted Zentmayer gave the world its best model for the microscope, and the lens which bore his name long filled a place entirely its own in photography, and when the Government placed the administration of the total eclipse expedition of 1869 in the hands of Professor Morton, then Secretary of the Institute, it was unnecessary to seek further for the complete solution of the then new practical optical questions involved in such an enterprise.

In chemistry, Dr. Crookes, by aid of photo-spectroscopy and orthochromatic plates, has added the metal monium to the list, with its characteristic lines far out in the ultra invisible light, in the phosphorescent glow of yttria under molecular bombardment in vacuo. Meteorological science is enriched by photography. It is pertinent to mention the interesting contributions of W. N. Jennings, of the Institute, to the study of lightning dis

charges, and the work of C. Francis Jenkins in the conversion of a scientific toy into the phantascope, which has found its extension in the kinetoscope, and which earned for him the Cresson medal of the Institute. The kinetoscope, with its miles of photographic films, as exhibited first by our H. R. Heyl, has found applications unanticipated in recording the movements during a solar eclipse and of growing plants, and has gone to the front with the army in Africa. In the industries the applications of photography are of infinite variety in character and importance. It is proposed to furnish cards for the Jacquard loom, and thus make tapestries commonplace. It will furnish water-marks for paper capable of 109,000 impressions. It reproduced the Encyclopædia Britannica at one-third the cost of typc. It preserved the valuable MS. copy of Century Dictionary, which was practically uninsurable, in miniature form against loss by fire. It may, in the future, in the same way, find a place to economize shelf-room in our libraries by compressing books that are seldom or never read. Its applications are well known in the copying of inscriptions, even in dark interiors, in the preservation and duplication of valuable documents and papers, in the detection of forgeries, especially by the method of composite photography as developed by Dr. Persifor Frazer, in the furnishing of legal evidence in general, in the detection of criminals, etc. In Canada, 50,000 square miles have been platted by means of the photo-theodolite. In the late war the camera went to the front, and has furnished invaluable records. Apropos of this, it is only necessary to recall Capt. Wise making exposures while charging up San Juan Hill. In the present African war it promises to play an important part in reconnoissance through the telephoto apparatus that accompanies the British forces.

In its purely commercial aspects this subject is one of growing importance. The demands, at present great, are rapidly increasing with new applications and expansion of those now in use. Outside of the industries consuming photographic goods. there are at least 1,500,000 amateurs in the United States, generally regarded as gross consumers. The industries supplying photographic wants are necessarily of the most varied character. Companies supplying them are continually increasing their plants. It is difficult to get at the amount of business and profits, but the published statement of one company originating in America, now in England and America, announced a dividend of 20 per cent. in Dece nber last, with repeated interim.

dividends, on a capital of $8,000,000. Other companies show similar prosperity. One article, largely consumed, may be particularly mentioned, which America does not seem able yet to produce of best quality, namely, paper, and it is well for manufacturers to remember that in photography, only the best of everything is good enough.-Journal of the Franklin Institute, December, 1899.



Some time ago we were interested in finding out how generally the elements of astronomy was regularly pursued in the colleges and secondary schools of the United States. The result of a limited inquiry was, that in the colleges the study of astronomy appears very commonly in some courses and good modern textbooks have been adopted very generally. From all that could be learned, however, in regard to the way the study was taught in some colleges, there seemed to be room for improvement.

In the secondary schools the results obtained were astonishing beyond measure. We are not now prepared to make a statistical statement to support the impression on our mind made by it, but it may at present suffice to say that about one-fourth of the high schools in the United States have the study of the elements of astronomy at all in the regular courses of study now pursued. We think this statement will be borne out by a full and complete canvass of such schools in this country.

Some years ago, it was our privilege, by request of Dr. Harper, President of the University of Chicago, to sit with the committee of ten to consider and report on what requirements should be generally adopted as suitable for entrance to college in the branches of physics and astronomy. The committee of ten was made up of representative scholars and teachers of science (if the writer's name be not thought of now) from widely different parts of the United States. In the deliberations of that committee it was very soon apparent that but two members of it had any interest at all in the study of astronomy as a means of preparation to enter college and but for those two persons, it was more than probable that it would have been reported by that committee that the elements of astronomy should not be one of the requirements to enter college in any of its regular courses.

These things are mentioned that it may be known more gener

ally what is a prevailing opinion among representative school men of the worth of this branch of study to find a place in the secondary courses of training. It is a very pertinent question for any educator to ask why this is so. These same committee men referred to above were enthusiastically interested in the study of physics and methods of teaching it in the laboratory, and they were unitedly urgent that more time should be given to this branch, even a whole year in the ordinary high school course. This condition of things could be explained by the facts that these men were teachers of elementary physics and that they had little, if anything, in later years, to do with the branch of astronomy. They did not seem to be informed in regard to the later and the better methods of teaching astronomy in secondary schools and in colleges.

In view of these facts and others like them that might be named, it is important that something should be done to put the study of the elements of astronomy in these grades of instruction on the right basis. No one says that astronomy is not one of the best and the noblest of the sciences. All believe that it should have prominent place in every college curriculum. But where it shall find place, how much time shall be given to it, and when it shall be taught are the minor points which each institution can settle for itself. But the method by which it shall be taught is common ground for all and much careful attention should be given to this side of the matter, and what we have further to say will bear on this point.

1. What ought to be done and what can be done to give elementary astronomy its proper place in courses of study for secondary schools? It is first necessary to bring to the attention of leading teachers and prominent school officers the value and place of astronomy as a disciplinary study. Those who are informed know that the advantages accruing to the student from a pursuit of this study are chiefly intellectual. The experienced teacher who can rightly advise as to the choice of studies, will never place favorable advice in the choice of astronomy as against biology or physics, on the ground that its pursuit and development will have direct bearing to enhance the material interests of mankind. It is not for a moment to be supposed that the discoveries of astronomy will at all compare in practical. value with those coming to us from chemistry and electricity for uses in the arts the manufacturing industries of the world that hold so large a place in the public thought of the present time. But it is true, as Professor Young has well and thought

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