Illustrated Catalogue Of Magic Lanterns (after November 1889, probably 1890)

46 MCINTOSH BATTERY AND OPTICAL CO., CHICAGO. ILL., U. S. A. artesian diver, Hydrometer; diffusion of gases; fountain in vacuo; siphon ; pyrometer; Torricelli’s experiment; Marriotte’s law ; the manometer; Sprengel’s air pump; influence of pressure on boiling point; conductivity of solids; convection ; thermo-pile ; umbra and penumbra; action of magnets; attraction and repulsion from elec- trical excitation. By means of diagrams and photographs the most recent inventions in the arts can be illustrated and explained. The apparatus we have described is adapted to daily use in all schools and educational insti- tutions, and we confidently claim that it will, when intelligently em- ployed, arouse greater interest, and afford a more valuable and varied means of illustration than many times its cost invested in other appa- ratus designed for object teaching. TESTIMONIALS. We have many inquiries in regard to the utility of the solar microscope and stereopticon in the illustration of scientific and popular lectures before classes of students and public audiences. In answer, we give a few of the many notices received. From Philadelphia Medical and Surgical Re- porter. Report of American Medical As- sociation, held at St. Paid, Minn. The last paper at the morning session was read by Dr. H. O. Marcy, of Boston, who had for his subject “ Uterine Tumors.” The method by which the lecture was demonstrated, the means used being a solar microscope and stereopticon, excited a large degree of interest, owing to the wonderful clearness and brightness of the subjects cast upon the screen. Aiter the termination of the lecture, in obedience to the expressed wish of many of the physicians, the inventor, Dr. L. D. McIntosh, of Chicago, explained fully the principles of this solar microscope, an ex- planation that was listened to with much interest and close attention. This solar miscroscope may truly be considered a great aid to scientific investigation. By its aid physiology, pathology, histology can be studied, with illustrations of genuine sec- tions. The circulation of the blood can be mirrored forth with startling distinct- ness; images of living animalculse, minute insects and aquatic animals, with all their motions, thoroughly portrayed, and in cases where they are transparent the beating of heart and movement of the internal organs are vividly shadowed forth upon the canvas in a degree of perfection almost beyond belief. It is a combined instrument, and can be used as an ordinary monocular microscope and as a stereopticon. It is, however, very simple in its arrangement, there being no complicated parts that are liable to get out of order. The stereopticon proper is similar in appearance to the ordinary stereopticon, sunlight, however, being used instead of artificial light. This combination adds much to the value of the invention, and its utility is very largely enhanced. Its use is not confined to phy- sicians and scientists, forit is an instrument that should be in all educational institutions of the higher grades. Its use as a means of instruction is of great value, as an object can be shown with equal facility to a large class or audience as to a single person. In the matter of economy, without taking into consideration the superiority of its work, it is in advance of the ordinary stereopticon, as sunlight is cheaper than artificial light. Another feature is that it is exceedingly portable, and can be placed in position in a very short time. The ordinarjr power is that of 500 diameters, although, with higher objectives.it is capable of attaining a power of 1,500 diameters. Taken altogether, it is truly an invaluable invention, and its use will be of an extended nature. From Martins’ Druggists' Directory. Report of the American Medical Association and Exhibits. Richmond, Va. Dr. L. D. McIntosh, of Chicago, occupied a prominent share of the interest taken in the exhibition. One of the most interesting features was a view shown with his solar microscope of a live frog’s foot, showing the circulation of the blood through the veins and arteries. Morris, 111. To whom it may concern: During the past year I have used Dr. McIntosh’s Solar Microscope and Stere- opticon in connection with school work. I recommended our Board of Education to purchase this instrument because I believed it would furnish an excellent means for a vivid illustration of topics in several sub- jects, and give pupils an added interest i "j