324 On the Oxide of Manganese of Nay gag. 



to be of an inferior quality, its specific gravity was greater, 

 because upon this supposition, and in order to make the loss 

 of weight in the silver amount to 88-103 grains, the spe- 

 cific gravity of this alcohol, compared with that of water, 

 must have been 0'920, But Mr. Biddle could not but be 

 mistaken with such a liquor, which was nothing more than 

 the most common spirits, and which, if I am not mistaken, 

 could not support the temperature of the experiment without 

 freezing. 



It appears, therefore, ascertained, that there is an error in 

 the weights ; and consequently we may conceive that, the 

 density of the solid mercury having been deduced from the 

 comparison of the results of these weights, the density has 

 been found so much the greater as the loss of the weight ia 

 silver had been expressed by too large a number. 



I have no intention to pre-judge the question relative to 

 <he density of solid mercury : I am far from wishing to raise 

 doubts upon the talents of Mr. Biddle, or upon the penetra- 

 tion of the members of the Philosophical Society of Birming- 

 ham, in whose presence and to whose satisfaction the ex- 

 periments of the former were made j but I think myself en- 

 titled to say, that the experiments, of which he has published 

 the results, ought at least to be made over again. Mr. Bid- 

 die's idea is a happy one, and I do not deny that these ex- 

 periments may lead to the solution of the problem. 

 I have the honour to be, &c. 



Tardy de La BROssy, 



LVIII. Analysis of the sulphuretted Oxide of Manganese of 

 Naygag. By M. VAuauELiN*. 



iVi. Klaphoth, having made an analysis of the sulphuret 

 of manganese under the name of sicbenlurghischen, disco- 

 vered that it is composed of 82 parts of oxide of manganese 

 at the minimum, or soluble in nitric acid; of five parts 

 of carbonic acid, and of eleven parts of sulphur, without 



* From Annales da Museum d'Histoire NatureHe, vol. vi. 



having 



