Inventions in the Century

by William Henry Doolittle

The Megaphone of Edison appeared, consisting of two large funnels having elastic conducting tubes from their apices to the aural orifice. Conversation in moderate tones has been heard and understood by their use at a distance of one and a half miles. The megaphone has been found very useful in speaking to large outdoor crowds.

But let us go back a little: In 1845, Chas. Bourseuil of France published the idea that the vibrations of speech uttered against a diaphragm might break or make an electric contact, and the electric pulsations thereby produced might set another diaphragm vibrating which should produce the transmitted sound waves. In 1857, another Frenchman, Leon Scott, patented in France his Phonautograph—an instrument consisting of a large barrel-like mouth-piece into which words were spoken, a membrane therein against which the voice vibrations were received, a stylus attached to this vibrating membrane, and a rotating cylinder covered with blackened paper, against which the stylus bore and on which it recorded the sound waves in exact form received on the vibrating diaphragm. Then came the researches and publications of Helmholtz and König on acoustic science, 1862-1866. Then young Philip Reis of Frankfort, Germany, attempted to put all these theories into an apparatus to reproduce speech, but did not quite succeed. Then in 1874-1875, Bell took up the matter, and at the Philadelphia exhibition, 1876, astonished the world by the revelations of the telephone. In April, 1877, Charles Cros, a Frenchman, in a communication to the Academy of Sciences in Paris, after describing an apparatus like the Scott phonautograph, set forth how traced undulating lines of voice vibrations might be reproduced in intaglio or in relief, and reproduced upon a vibrating membrane by a pointed stylus attached thereto and following the line of the original pulsations. The communication seems to have been pigeon-holed, and not read in open session until December, 1877, and until after Thomas A. Edison had actually completed and used his phonograph in the United States. Cros rested on the suggestion. Edison, without knowing of Cros’ suggestion, was first to make and actually use the same invention. Edison’s cylinder, on which the sounds were recorded and from which they were reproduced, was covered by tin foil. A great advance was made by Dr. Chichester A. Bell and Mr. C. S. Tainter, who in 1886 patented in the United States means of cutting or engraving the sound waves in a solid body. The solid body they employed was a thin pasteboard cylinder covered with wax. This apparatus they called the graphophone. Two years thereafter, Mr. Emile Berliner of Washington had invented the gramophone, which consists in etching on a metallic plate the record of voice waves. He has termed his invention, “the art of etching the human voice.” He prepares a polished metal plate, generally zinc, with an extremely thin coating of film or fatty milk, which dries upon and adheres to the plate. The stylus penetrates this film, meeting from it the slightest possible resistance, and traces thereon the message. The record plate is then subjected to a particularly constituted acid bath, which, entering the groove or grooves formed by the stylus, cuts or etches the same into the plate. The groove thus formed may be deepened by another acid solution. When thus produced, as many copies of the record as desired may be made by the electrotyper or print plater.

The public is now familiar with the different forms of this wonderful instrument, and like the telephone, they no longer seem marvellous. Yet it is only within the age of a youth or a maiden when the allegations or predictions that the human voice would soon be carried over the land, and reproduced across a continent, or be preserved or engraven on tablets and reproduced at pleasure anywhere, in this or any subsequent generation, were themselves regarded as strange messages of dreamers and madmen.

Optical Instruments.—There were practical inventions in optical instruments long before this century. Achromatic and other lenses were known, and the microscope, the telescope and spectacles.

The inventive genius of this century in the field of optics has not eclipsed the telescope and microscope of former ages. They were the fruits of the efforts of many ages and of many minds, although Hans Lippersheim of Holland in 1608 appears to have made the first successful instrument “for seeing things at a distance.” Galileo soon thereafter greatly improved and increased its capacity, and was the first to direct it towards the heavens. And as to the microscope, Dr. Lieberkulm, of Berlin, in 1740, made the first successful solar microscope. As well known, it consisted essentially of two lenses and a mirror, by which the sun’s rays are reflected on the first lens, concentrated on the object and further magnified by the second lens.

The depths of the stars and the minutest mote that floats in the sun beam reflect the glory of those inventions.

The invention of John Dolland of London, about 1758, of the achromatic lens should be borne in mind in connection with telescopes, microscopes, etc. He it was who invented the combination of two lenses, one concave and the other convex, one of flint glass and the other of crown glass, which, refracting in contrary ways, neutralised the dispersion of colour rays and produced a clear, colourless light.

Many improvements and discoveries in optics and optical instruments have been made during the century, due to the researches of such scientists as Arago, Brewster, Young, Fresnel, Airy, Hamilton, Lloyd, Cauchy and others, and of the labours of the army of skilled experts and mechanicians who have followed their lead.

Sir David Brewster, born in Scotland in 1781, made (1810-1840) many improvements in the construction of the microscope and telescope, invented the kaleidoscope, introduced in the stereoscope the principles and leading features which those beautiful instruments still embody, and rendered it popular among scientists and artists.

It is said that Prof. Eliot of Edinburgh in 1834 was the first to conceive of the idea of a stereoscope, by which two different pictures of the same object, taken by photography, to correspond to the two different positions of an object as viewed by the two eyes, are combined into one view by two reflecting mirrors set at an angle of about 45°, and conveying to the eyes a single reflection of the object as a solid body. But Sir Charles Wheaton in 1838 constructed the first instrument, and in 1849 Brewster introduced the present form of lenticular lenses.