The Progress of Invention in the Nineteenth Century.

by Edward W. Byrn

FIG. 197.—MODERN MICROSCOPE.

The Microscope.—Just as the telescope reveals the infinity of the great world above and around us, so does the microscope reveal the infinity of the little world around, about, and within us. Its origin, like the telescope, is hidden in the dim distance of the past, but it is believed to antedate the telescope. Probably the dewdrop on a leaf constituted the first microscope. The magnifying power of glass balls was known to the Chinese, Japanese, Assyrians and Egyptians, and a lens made of rock crystal was found among the ruins of Ninevah. The microscope is either single or compound. In the single the object is viewed directly. In the compound two or more lenses are so arranged that the image formed by one is magnified by the others, and viewed as if it were the object itself. The single microscope cannot be claimed by any inventor. The double or compound microscope was invented by Farncelli in 1624, and it was in that century that the first important applications were made for scientific investigation. Most of the investigations were made, however, by the single microscope, and the names of Borelli, Malpighi, Lieberkuhn, Hooke, Leeuwenhoek, Swammerden, Lyonnet, Hewson and Ellis were conspicuous as the fathers of microscopy. For more than two hundred and fifty years the microscope has lent its magnifying aid to the eye, and step by step it has been gradually improved. Joseph J. Lister’s aplanatic foci and compound objective, in 1829, was a notable improvement in the first part of the century, and this has been followed up by contributions from various inventors, until the modern compound microscope, [Fig. 197], is a triumph of the optician’s art, and an instrument of wonderful accuracy and power. Its greatest work belongs to the Nineteenth Century.

Multiplying the dimensions of the smallest cells to more than a thousand times their size, it has brought into range of vision an unseen world, developed new sciences, and added immensely to the stores of human knowledge. To the biologist and botanist it has yielded its revelations in cell structure and growth; to the physician its diagnosis in urinary and blood examinations; in histology and morbid secretions it is invaluable; in geology its contribution to the knowledge of the physical history of the world is of equal importance; while in the study of bacteriology and disease germs it has so revolutionized our conception of the laws of health and sanitation, and the conditions of life and death, and is so intimately related to our well being, as to mark probably the greatest era of progress and useful extension of knowledge the world has ever known. In the useful arts, also, it figures in almost every department; the jeweler, the engraver, the miner, the agriculturalist, the chemical manufacturer, and the food inspector, all make use of its magnifying powers.

To the microscope the art of photography has lent its valuable aid, so that all the revelations of the microscope are susceptible of preservation in permanent records, as photomicrographs. A curious, but very practical, use of the microscope was made in the establishment of the pigeon-post during the siege of Paris in 1870-71. Shut in from the outside world, the resourceful Frenchmen photographed the news of the day to such microscopic dimensions that a single pigeon could carry 50,000 messages, which weighed less than a gramme. These messages were placed on delicate films, rolled up, and packed in quills. The pigeons were sent out in balloons, and flying back to Paris from the outer world, carried these messages back and forth, and the messages, when reaching their destination, were enlarged to legible dimensions and interpreted by the microscope. It is said that two and a half million messages were in this way transmitted.

The Spectroscope.—To the popular comprehension, the best definition of any scientific instrument is to tell what it does. Few things, however, so tax the credulity of the uninformed as a description of the functions and possibilities of the spectroscope. To state that it tells what kind of materials there are in the sun and stars, millions of miles away, seems like an unwarranted attack upon one’s imagination, and yet this is one of the things that the spectroscope does. A few commonplace observations will help to explain its action. Every schoolboy has seen the play of colors through a triangular prism of glass, as seen in [Fig. 198], and the older generation remembers the old-fashioned candelabras, which, with their brilliant pendants of cut glass cast beautiful colored patches on the wall, and whose dancing beauties delighted the souls of many a boy and girl of fifty years ago. This spread of color is called the spectrum, and it is with the spectrum that the spectroscope has to deal. The white light of the sun is composed of the seven colors: red, orange, yellow, green, blue, indigo, and violet. When a sunbeam falls upon a triangular prism of glass the beam is bent from its course at an angle, and the different colors of its light are deflected at different angles or degrees, and consequently, instead of appearing as white light, the beam is spread out into a divergent wedge shape, that separates the colors and produces what is called the spectrum. This discovery was made by Sir Isaac Newton, in 1675.