285 



portions of 50, 30, and 20, he thinks it no great violation of proba- 

 bility, to suppose that experiments affected with no error would, in 

 fact, have given these integral results instead of the former decimal 

 parts. 



Mr. Smithson proceeds further to express his doubts, not only of 

 the existence of quadruple, but even of strictly triple compounds. He 

 believes that all combination whatever is binary, and is inclined to 

 consider the present compound as consisting of equal parts of galena 

 and fahlertz ; the latter being also a binary compound of the sulphu- 

 rets of antimony and of copper, in the proportion of three of the for- 

 mer to two of the latter. 



The author next computes the proportion of the four ultimate ele- 

 ments ; and these, being deduced from assumed simple fractions, are 

 simply as the numbers 12, 25, 15, and 8. These, he remarks, are 

 sexagesimal parts of this ore, as were those also which in a former 

 paper he assigned to calamine. 



When in that communication he offered a system founded on the 

 results of his own experiments, he is apprehensive that he may have 

 been supposed to be influenced, even unconsciously to himself, by a 

 favourite theory ; but the present case he thinks not liable to the 

 same objection, since no fondness for theory affected the experiments 

 of Mr. Hatchett, which nevertheless accord with its principles when 

 viewed in a proper light. 



Mr. Smithson, conceiving it established that chemical compounds 

 consist of elements united in simple proportions by weight, observes, 

 that greater accuracy is to be expected from correct theory than can 

 be obtained in chemical experiments. 



The principles of his theory require that simple ratios should 

 always obtain in binary compounds ; and he gives instances from the 

 subjects of the foregoing experiments, which any chemist can, by 

 careful repetition, confirm. 



The ratios which he assigns to the compounds of lead are such, 

 that two parts of lead make three of sulphate of lead, and five of lead 

 make six of sulphate of lead. So also five of antimony make six of 

 sulphuret, and three of antimony make four of powder of algaroth. 



From the only crystalline form which Mr. Smithson believes to 

 exist of the triple sulphuret, he infers that its primitive form is a 

 cube, and not a tetrahedral prism, as stated by Count Bournon ; and 

 he observes, that the angles given by the Count are at variance with 

 each other. 



Ore Oxalic Acid. By Thomas Thomson, M.D. F.R.S.Ed. Commu- 

 nicated by Charles Hatchett, Esq. F.R.S. Read January 14, 1808. 

 [Phil Trans. 1808, p. 63.] 



Though much important information has resulted respecting the 

 formation of this acid, from the experiments of Hermbstadt, Westrumb, 

 Berthollet, Fourcroy, and Vauquelin, the properties of it have been 

 rather neglected since the original dissertation of Bergman, to whom 



