Scientific Intelligence. 313 



tute for galls ; but unfortunately, like the extract of quercitron, 

 it affords with iron nothing but a meagre olive ; and Dr. Ban- 

 -croft states, that in a great number of trials, he was unable, by 

 the greatest accumulation, to produce any thing like a black, 

 even upon wool, much less upon cotton and silk. 



A singular fact, which I observed in the course of my expe- 

 riments, is worthy of notice. I had prepared for a certain 

 purpose, solutions from the wood of the trunk of a tree, about 

 three feet, and from that of a limb about three inches in di- 

 ameter. The same quantity of wood and of the solvent was 

 employed in both cases. On adding to each the same quan- 

 tity of the solution of gelatine, abundant precipitates immedi- 

 ately appeared, as usual, apparently much the same in quantity; 

 but to ray astonishment, the size of the several congeries in 

 each, bore a near proportion to that of the sticks from which 

 they were obtained, not differing much from that of middling 

 and of very small flakes of snow. Is not this an extraordinary 

 fact, evincive of a complication in the arrangement of these 

 bodies hitherto unsuspected. May it not at some future pe- 

 riod, lead to a nomenclature of precipitates ; affording, like the 

 chrystallographyofHaiiy, a new and accurate mode of determin- 

 ing the compositions of substances ; and perhaps throwing light 

 upon the obscure subject of chemical, or if you please, electro- 

 chemical affinities. The size of a stick might probably be as- 

 certained with almost as much precision, as by actual admea- 

 surement. The solutions in this experiment, were formed by 

 maceration in cold weather. When hot water was employed, 

 and the process was completed in two or three hours, the ap- 

 pearance of the precipitate was very different, the congeries 

 being smaller, irregular, and not well defined. 



I have only to add, that having taken measures to secure the 

 discovery, both in this country and Europe, it is my wish to 

 bring it into general use as speedily as possible. 

 I am, Sir, very respectfully. 



Your obedient servant, 



WILLIAM SHELDON. 



P. S. In a short article for some future number, I may send 

 you an account of the operation of the machine, and of some 

 other particulars. 



