Intelligence and Miscellaneous Articles. 545 



The advantages which this process possesses over every other 

 must be, I think, apparent. The papers are prepared in the most 

 simple manner, and may be kept ready by the tourist until required 

 for use. They require no preparation previously to their being 

 placed in the camera, and they can be preserved until a convenient 

 opportunity offers for bringing out the picture, which is done in the 

 most simple manner, with a material which can be anywhere pro- 

 cured. 



Anxious to give the public the advantage of this process during 

 ,the beautiful weather of the present season, I have not waited to 

 perfect the manipulatory details which are necessary for the produc- 

 tion of portraits. It is sufficient, however, to say, that experiment 

 has satisfied me of its applicability for this purpose. 



Prismatic examination has proved that the rays effecting this che- 

 mical change are those which I have elsewhere shown to be perfectly 

 independent of solar light or heat. I therefore propose to distin- 

 guish this process by a name which has a general rather than a par- 

 ticular application. Regarding all photographic phenomena as due 

 to the principle Energia, I would nevertheless wish to distinguish 

 this very interesting process as the Energiatype. 



I enclose you a few specimens of the results already obtained. 

 The exceeding sensibility of the Energiatype is best shown by an 

 attempt to copy engravings or leaves by it. The three specimens I 

 enclose were produced by an exposure of considerably less than one 

 second. — Athenceum. 



In a subsequent number of the ' Athenaeum,' Mr. Hunt has given 

 the following additional directions : — 



Experience has suggested to me the advantage of adding to the 

 solution of succinic acid and gum, as previously given, 5 grains of 

 common salt. This preserves the lights very clear, and indeed im- 

 proves the sensibility of the paper. 



When the solution of the sulphate of iron is laid over the paper, 

 it is requisite to keep disturbing it, by rapidly but lightly brushing 

 it up; otherwise numerous little black specks form, which destroy 

 the photograph. If, as sometimes happens, the surface of the pic- 

 ture blackens all over, it must not be concluded that the drawing is 

 destroyed. The whole of this superficial blackness may be removed 

 by immediately washing with a wet sponge. If the lights become 

 in any way discoloured, a little exceedingly diluted hydrochloric 

 (muriatic) acid will restore them to their proper degree of white- 

 nesss ; but care must be taken that the acid is speedily washed off, 

 or the shadows will suffer. 



When, from the shortness of the exposure, the image developes 

 itself slowly or imperfectly, a slight degree of warmth brings out 

 the picture with rapidity and force. Holding the paper a short di- 

 stance from the fire is the best mode of operating. 



METHOD OF PRESERVING ANIMAL SUBSTANCES. BY M. GANNAL. 



From the observations made by M. Gannal, and reported to the 

 Acad£mie des Sciences at a recent sitting, it appears that arsenic 



Phil. Mag. S. 3. No. 162. Suppl. Vol. 24. 2 N 



