142 ANNUAL OP SCIENTIFIC DISCOVERY. 



woiulorful, viewed moi-ely as a question of economies. Neverthe- 

 less, some of tlie fai-ts are sufficiently startling. Twenty years a<2:o, 

 one person elaimrd the sole right to praetiee piiotogi;i])liy i)rol'es- 

 sionally, in Knglaiul. Aecording to the census of ISGl, the number 

 of persons who entered their names as photoyrai)lu'rs was 2, Hoi. 

 There is reason, however, to believe that these ligin-es fall short of 

 the real niinilti'i-. Sinee tlu-u it is probable the number has been 

 donljled or trebled, and that, inehiiliiig those collaterally associated 

 with the art, it is even four or live times that number. But these 

 figures fall far short of the number interested in photography as am- 

 ateurs. We are informed that eight years ago, in estaijlisliing a 

 j)enodieal whieh ha-; since become the leading ph<)togra])hic jour- 

 nal, a large j)ubli>hing lirm sent out twenty-live thousand circulars 

 — not sown broadcast, but specially addressed to persons known 

 to ije interested in the new art-science. The nimiber of professional 

 piiotographers in the United States is said to be over fifteen thou- 

 sand, and a proportionate number may with propriety be estimated 

 as spread over continental Europe and other i)arts of the civilized 

 glol)e. 



But a more curious estimate of the ramifications of this industry 

 may be formed by a glance at the consumption of some of the ma- 

 terials employed. A single firm in London consumes, on an aver- 

 age, the whites of two thousand eggs daily in the manufacture of 

 allnunenized paper for photographic printing, amounting to six 

 hundred thousand annually. As it may fairly be assumed that this 

 is but a tenth of the total amount consumed in this country, we 

 obtain an average of six millions of inclKKite I'owls sacrificed annu- 

 ally, in this new worship (tftiie sun, in the United Kingdom alone. 

 "NViien to this is added the far larger consumption of Europe and 

 America, which we do not attempt to put in figures, the imagina- 

 tion is startled by the enormous total inevitably presented for its 

 realization. 



In the absence of exact data, we hesitate to estimate the con- 

 sumption of the precious metals, the mountains of silver and mon- 

 uments of gokl, which follow as matters of necessity. A calcula- 

 tion, based on facts, enables us to state, however, that for every 

 twenty thousand eggs employed, nearly one hundred weight of 

 nitrate of silver is consumed. We arrive thus at an estimate of 

 three hundred hundred weight of nitrate of silver annually tiscd in 

 this countr}' alone in the proiluction of photographs. To descend 

 to individual facts more easily grasped, we learn that the eon- 

 sumption of materials in the photogi'aphs of the International Ex- 

 hibition of 1802, produced by Mr. England for the London Stereo- 

 scopic Company, amounted to twenty-four ounces of nitrate of 

 silver, nearly fitty-four ounces of terchloride of gold, two hundred 

 gallons of albumen, amounting to the whites of thirty-two thou- 

 sand eggs, and seventy reams of paper ; the issue of pictures ap- 

 proaching to nearly a million, the number of stereoscopic prints 

 amounting to nearly eight hundi-ed thousand copies. — Scientijic 

 American. 



