S'dO Biographical Account of [MaYs 



species of bark from St. Domingo^ which was considered at the 

 time as a model for vegetable analysis. It bears the exact . 

 <;haracters of the peculiar method foflowed by Vauqueiin. I 

 should suppose therefore, though nodiing is said on the subject, 

 that the experiments were contrived and executed by that emi- 

 nent chemist. 



8. His dissertation on the sulphate of mercury, though imper- 

 fect, contains some good observations, and facilitated the know- 

 ledge of metallic salts, which was at that time very imperfect; 

 but has been greatly improved since. The same remark applies 

 to his subsequent memoirs on the action of ammonia, on the 

 sulphate, nitrate, and jnuriate, of mercury. These papers contain 

 some mistaken opinions, though the formation of the triple 

 salts, which constitutes the basis of his opinion, be correct. 



9. His experiments on the brain contains several valuable 

 facts, and his opinion ai proaches to accuracy. The subject has 

 been recently resumed by Vauqueiin, who has published a 

 curious dissertation on it, which we shall insert in the present 

 number of the Annals of Philosophy. 



10. The analysis of tears, and the mucus of the nose, by 

 Fourcroy and Vauqueiin, is valuable ; though it contains some 

 mistakes, from the too hasty application of an erroneous theory 

 to the animal phenomena. 



11. The analysis of urine, and of urinary calculi, by the 

 same gentleman, has been much admired on the Continent, and 

 no doubt contains many important facts; but hardly any impor- 

 tant addition is made in it to the dissertation of Dr. Wollaston 

 on the same subject, which had been already published in the 

 Philosophical Transactions, To this very importaiit paper no 

 allusion whatever is made ; yet they could hardly be ignorant of 

 it, as they quote Dr. Pearson's essay on the same subject, which 

 liad been published in the same work. 



12. Their experiments on the combustion of bodies in oxymu- 

 riatic acid gas, and the detonations which take place when 

 hyperoxymuriate of potash and a combustible substance are 

 mixed together and struck upon an anvil, are curious, though 

 Ihey add but little to the improvement of the theory of che- 

 mistry. 



13. Their method of obtaining barytes in a state of purity, by 

 exposing the nitrate of barytes to a red heat in a porcelain 

 crucible, is a good one ; and is by far the easiest way to procure 

 that earth in a state of tolerable purity. 



14. Their theory of the formation of sulphuric ether, by the 

 action of sulphuric acid, is plausible ; and at least as likely to be 

 true as any other explanation which has been hitherto otFered i 

 but they were v/rong in attempting to extend that theory to the 



