12i YEAR-BOOK OF FACTS. 



the circular hole by which the pattern is suspended, and so imparts 

 to it a shaking motion just sufficient to fill up the pattern with all 

 the colours on the disc below, but then lost to the eye by its rapid 

 revolution. If the pattern were perfectly still, the colours would 

 not appear ; but if allowed slight motion as above described, the 

 colours are reproduced upon the principle — that of images being 

 retained upon the eye, which is thus elucidated in a very beauti- 

 ful manner. — Described and Figured in the Mechanics Magazine. 



CRYPTOGRAPHY. 



Mr. R. A. Brooman has patented a Crytographic Machine, or 

 apparatus for carrying on secret correspondence. 



The object of this invention is to provide a machine or apparatus, by means of 

 which secret correspondence, tor diplomatic and other purposes, may be carried 

 on conveniently and so as effectually to prevent the deciphering of the de- 

 spatches by any person not in possession of the key to the same. The main fea- 

 ture of the invention consists in the employment of several pairs of alphabets, 

 one alphabet of each pair being capable of longitudinal motion along toe other, 

 so as to bring different letters of the two alphabets opposite each other. By 

 arranging the several pairs of alphabets according t>> positions indicated by means 

 of a " key-word" and a standard pair of alphabets, and transmitting in succes- 

 sion the letters found on one of the two alphabets opposite to the proper letters 

 of the despatch on the other, the several pairs of alphabets being successively 

 used, a despatch in cipher may be sent, which despatch may be readily inter- 

 preted by reading the letters of one of the sets of alphabets found opposite to 

 the received letters on the other set — or, in other words, by reversing the sending 

 process. In the machine or apparatus devised by the inventor for these pur- 

 poses, the moveable alphabets are printed or written on endless bands or tapes, 

 which pass round rollers, and maybe driven by pinions or otherwise. All tho 

 pairs of alphabets are mounted on an axle, which is caused to rotate by a crank 

 handle or otherwise, so as to bring successive pairs of alphabets into view. — 

 Mechanics' Magazine. 



IMPROVED HARMONIUMS. 

 In this improvement, patented by Professor Wheatstone, the wind 

 chest is placed above the somnier, and the somnier itself is inverted, 

 having its note frames and vibratory above, and its palettes or valves 

 below, and opening downwards ; so that by causing one of their ends 

 to project beyond the front board of the BOmnier, the plungers of 

 the linger keys can be made to act directly upon the pain,-, 

 and open tin; valves required. Tho wild apparatus is placed ver- 

 tically in the instrument, and consists of three cuckoo bellows, two 

 of which serve as feeders, and the third as a reservoir. The feeders 



are actuated by two pedals or treadles, to which they an connected 



by bands Or straps passing over small pulleys secured to the back 



board of the r e ser v o ir, thus dispensing with the lever spindle and 

 short arm of the ordinary instrumenti The wind which enti ra the 

 feeders in these instruments wh d distended by their internal springs 

 is forced by the descent of the trejkdles through valves iii the middle 

 board of the bellows into the reservoir, from a hence it passes through 

 wind paasages at the back of the reservoir, and through the Bomnier 

 into the wind chest. — Ibid. 



