Curiosities of Science. 45 



power of inductive search and of philosophical deduction, presented the 

 world with a class of discoveries which showed how vast a field of inves- 

 tigation was opening for the younger races of mankind. 



The first attempts in photography, which were made at the insti- 

 gation of M. Arago, by order of the French Government, to copy the 

 Egyptian tombs and temples and the remains of the Aztecs in Central 

 America, were failures. Although the photographers employed suc- 

 ceeded to admiration, in Paris, in producing pictures in a few minutes, 

 they found often that an exposure of an hour was insufficient under the 

 bright and glowing illumination of a southern sky. 



THE BEST SKY FOR PHOTOGRAPHY. 



Contrary to all preconceived ideas, experience proves that 

 the brighter the sky that shines above the camera the more 

 tardy the action within it. Italy and Malta do their work 

 slower than Paris. Under the brilliant light of a Mexican sun, 

 half an hour is required to produce effects which in England 

 would occupy but a minute. In the burning atmosphere of 

 India, though photographical the year round, the process is 

 comparatively slow and difficult to manage ; while in the clear, 

 beautiful, and moreover cool, light of the higher Alps of Eu- 

 rope, it has been proved that the production of a picture re- 

 quires many more minutes, even with the most sensitive pre- 

 parations, than in the murky atmosphere of London. Upon 

 the whole, the temperate skies of this country may be pro- 

 nounced favourable to photographic action ; a fact for which 

 the prevailing characteristic of our climate may partially ac- 

 count, humidity being an indispensable condition for the 

 working state both of paper and chemicals. Quarterly Review. 

 No. 202. 



PHOTOGRAPHIC EFFECTS OF LIGHTNING. 



The following authenticated instances of this singular phe- 

 nomenon have been communicated to the Royal Society by 

 Andres Poey, Director of the Observatory at Havana : 



Benjamin Franklin, in 1786, stated that about twenty years previ- 

 ous, a man who was standing opposite a tree that had just been struck 

 by "a thunderbolt" had on his breast an exact representation of that 

 tree. 



In the New-York Journal of Commerce, August 26th, 1853. it is re- 

 lated that " a little girl was standing at a window, before which was a 

 young maple-tree ; after a brilliant flash of lightning, a complete image 

 of the tree was found imprinted on her body." 



M. Raspail relates that, in 1855, a boy having climbed a tree for 

 the purpose of robbing a bird's nest, the tree was struck, and the boy 

 thrown upon the ground ; on his breast the image of the tree, with the 

 bird and nest on one of its branches, appeared very plainly. 



M. Olioli, a learned Italian, brought before the Scientific Congress 

 at Naples the following four instances : 1. In September 1825, the fore- 

 mast of a brigantine in the Bay of St. Arniro was struck by lightning, 

 when a sailor sitting under the mast was struck dead, and on his back 



