AND RESEARCHES OF JAMES SMITHSON, 131 



The experiments were made to determine the properties 

 and composition of the substance. 



7. In the Transaction of the Royal Society, vol. cviii., 

 for 1818, p. 110, are u A few facts relative to the coloring mat- 

 ters of some vegetables." Read December 18, 1817. 



The vegetables particularly examined and described in 

 this paper are : 



a Turnsol, (litmus,) 



b The violet. 

 c Sugarloaf paper. 



d Black mulberry. 



e The common poppy. 



/ Sap green, and 



g Some animal greens. 



The above paper is chiefly an account of experiments 

 made for the purpose of testing the chemical characters ot 

 the coloring materials of the different substances an ex- 

 ceedingly interesting branch of inquiry in organic chemis- 

 try scarcely much advanced at this day beyond the point 

 at which Mr. Smithson left it. 



From the period of 1818, Mr. Smithson appears to have 

 ceased his contributions to the Transactions of the Royal 

 Society. After this time we find his name most frequently 

 occurring in the Annals of Philosophy, a work too well 

 known to require any remarks upon its scientific character. 



8. In this periodical, vol. xiv., 1819, is a letter from Mr. 

 Smithson, dated Paris, May 22, 1819, relative to u plombe 

 gomme," in which he claims the discovery of the composi- 

 tion of that substance for his " illustrious and unfortunate 

 friend, and indeed distant relative the late Smithson Ten- 

 nant," who he asserts had ascertained that it was a combi- 

 nation of oxide of lead, alumina and water. 



He describes the ore, its reactions and modes of reduction. 

 The alumine was detected by the usual test of igniting, wet- 

 ting the whitened mass with nitrate of cobalt, and again 

 igniting producing a blue color. 



It decrepitated wh6n heated in a glass tube over a candle, 

 and deposited water in the upper part of the tube, thus 

 proving it to be a hydrate. 



9. In the Annals, same vol., page 96, is another letter 

 dated Paris, May 19, 1819, (three days before the preced- 

 ing,) in which he describes a native sulphuret of lead and 

 arsenic, found in Upper Valais, in Switzerland, in a granose 

 compound of carbonate of lime and magnesia. 



