OPTICAL ASSOCIATION.

Otago Daily Times, Issue 20283, 16 December 1927, Page 3

OPTICAL ASSOCIATION.

AN INTERESTING ADDRESS. A large meeting of friends and members of the Otago and Southland, Optical Association gathered in the Y.M.C.A. Hall on Monday evening to hear an address by Mr G. A. Rawson on “ The Simple Optics of the Microscope,” and although the subject was a difficult one to handle, yet the speaker .was very successful in making his lecture perfectly clear even to those who had no knowledge of optics. During the course of the lecture Mr Rawson paid a glowing tribute to the development of the high class lens by British makers. In the early days of the microscope the workers were limited to the comparatively imperfect lenses which had been calculated and made, and it was not until 1886 that Professor Ernst Abbe, after many years of extensive research, introduced a new type of glass. This was made by the Carl Zeiss Company at the Jena Glass Works in Germany. This firm placed on the market a great variety of optical glasses, and for many years following this discovery Continental opticians had a monopoly m high-class lens making. In later years, however, the British makers have gradually come up to a level with the Continental makers, and indeed we have at the present time several British makers whose lenses are. superior to those of Continental origin. The development of the microscope, as it is known to-day, has opened up a great field for scientific research, and, even without going into the fields of research, vast and interesting fields are laid open to the amateur. To demonstrate this fact Mr Rawson then proceeded to show by means of the projection microscope, an instrument used m conjunction with the optical lantern, a series of misroscopic slides depicting objects with which everyone is perfectly familiar. The first part of this demonstration was confined to specimens suitably stained and mounted, and the beautiful results which were shown on such commonplace subjects as sections through pieces of wood and different common garden flowers were surprising. The lecturer also demonstrated a number of slides showing living specimens such as mites in cheese and different forms of water insects. One particular elide created a good deal of interest, a specimen of pond water with a number of water fleas which showed quite as lively characteristics as the better known variety. It was possible to distinguish the heart beating in one of these small insects owing to the great magnification used in the microscope. One can readily appreciate the immense value of the microscope in teaching more about the wonders of Nature, and it is really surprising that in these days of advanced education that more is not heard of the place of the microscope and the projection microscope in use for teaching school children such subjects as botany and physiology. A very wide field of utility could be opened up along these lines. At the conclusion of the lecture - very hearty vote of thanks was accorded Mr Rawson for the trouble he had gone to in preparing his very interesting subject.