474 Intelligence and Miscellaneous Articles. 



lead as a sulphuret (Pb S.). The latter was dried and the quantity 

 of lead calculated. The solution, containing the antimony in the 

 state of a sulphuret, was carefully neutralized by dilute muriatic or 

 acetic acid, and the precipitate collected upon a weighed filter, dried, 

 weighed, and a portion of it reduced to the metallic state by means 

 of a stream of dry hydrogen gas, as described by Rose, Analytical 

 Chemistry, vol. ii. After the quantity of each metal was thus 

 ascertained, the state of the oxidation of the antimony was still re- 

 quired. For this purpose the lead found was calculated as an oxide. 

 This weight added to the weight of the antimony, deducted from 

 the weight of the sample examined, gives the quantity of oxygen 

 combined with the antimony. 



The experiments which were performed upon several diiFerent 

 samples of this colour as usually found in commerce, proved it to 

 be a compound of oxide of lead with antimonious acid (Antimon 

 saure). But one sample received from Paris of great beauty turned 

 out to be a mixture of white lead and sulphuret of cadmium. — Pog- 

 gendorfs Annals, No. V. 1838, p. 135. 



EXTRACT FROM A LETTER FROM PROFESSOR JOHNSTON ON 

 THE ANALYSIS OF THE RESINS. 



Durham, Oct. 27, 1838. 

 My dear Phillips, — I am desirous of acquainting you with the 

 partial results of an investigation in which I am occupied, and 

 which I think will prove very interesting. I have been analysing 

 some of the resins, and so far as I have gone, I think they may 

 all be represented by a modification of the formula C^g H30, that for 

 oil of turpentnie, the carbon being constant and the hydrogen vari- 

 able. You are aware, probably, that the three resins hitherto ana- 

 lysed agree with this view, thus : 



p , 1 _ / C40 H32 O4. Rose. 



^ ^ ~ \ C40 H3Q O4. Liebig and Laurent. 

 Crystallized elemi C^o H32 O^. Rose. 

 Crystallized animi C40 Hgj O. Laurent. 

 Circumstances have led me to examine various other resins, with 

 the following results : 



Middletonite C40 H22 O^ 

 Gamboge C40 Ho4 O^ ? 



Guyaquillite C40 H;j(j 0(j 



E. India Animi 

 Copal B 



Highgate resin C40 H32 O 

 Mastic "1 n xj r\ 



Copal A / ^4oH32 04 



The sparingly soluble part of copal is B. That which easily dis- 

 solves is the same as the easily soluble part of mastic. The small 

 difficultly soluble part of the latter differs from copal B, at least in 

 properties. Berengelite C4oH3,08 



General formula = C4,, H3c,+ x Oij. 



This last resin is one said to occur abundantly in a kind of pitch 



? L/4n rlqi Ui 



