Intelligence and Miscellaneous Articles. 171 



glass tube, and was placed in a stove, the temperature of which could 

 be raised at pleasure. By heating this stove to 300° C, and at the 

 same time passing a current of dry air deprived of carbonic acid, all 

 the water which the magnesite contained was removed with cer- 

 tainty ; but at the same time carbonic acid was disengaged, which 

 it was requisite to collect and estimate. For this purpose the cur- 

 rent of air was directed, at its exit from the tube, into two vials con- 

 taining perfectly transparent barytes water. The carbonate of barytes 

 collected at the conclusion of the drying was estimated in the state 

 of sulphate ; and the quantity of carbonic acid, which the weight of 

 the sulphate represented, was added to that obtained by the follow- 

 ing operation. 



The residue which remained in the tube, after being weighed, was 

 calcined at a strong red heat ; the loss of weight indicated almost 

 the whole of the carbonic acid contained in the mineral ; the cal- 

 cined residue still contained a trace of it. To determine its amount, 

 the authors dissolved the residue in hydrochloric acid, and passed 

 over the hot solution a current of air, which removed some traces of 

 carbonic acid, and which were deposited in perfectly clear barytes 

 water. Thus the whole quantity of carbonic acid which a given 

 weight of the magnesite contained, consisted of — 1, the portion re- 

 moved by drying at 300° ; 2, that expelled by calcination ; 3, the 

 small portion which remained in the calcined residue. 



All these experiments were performed and considered with suffi- 

 cient care, and gave satisfactory results. The eleven last determi- 

 nations, which the authors deem most worthy of confidence, gave a 

 mean of 250-34 as the equivalent of magnesium. 



As all the errors which may be committed in such delicate analyses 

 tend rather to lower the real number, MM. Marchand and Scheerer 

 are of opinion, that, neglecting the insignificant fraction of thirty- 

 four hundredths, the round number 250 may be adopted as the equiva- 

 lent of magnesium, that of oxygen being 100, or 20, taking the equi- 

 valent of hydrogen as unity. According to this statement, 100 parts 

 of magnesia consist of 60 magnesium and 40 oxygen ; and 100 parts 

 of carbonate of magnesia are constituted of 47-619 carbonic acid and 

 52-38 of magnesia. 



The researches of MM. Marchand and Scheerer place magnesium 

 among the number of simple substances, the equivalents of which 

 are multiples of that of hydrogen by a whole number. — Journ. de 

 Pharm. et de Chim., Decembre 1850. 



ON A SERIES OF ALKALOIDS HOMOLOGOUS WITH AMMONIA- 

 METHYLAMINE. BV M. A. WURTZ. 



The process by which this base was obtained does not differ from 

 that employed by cliemists for preparing ammonia. The hydrochlo- 

 rate of methylamine, jierfectly dried, is mixed with twice its weight 

 of lime, and the mixture is introduced into a long tube closed atone 

 end, 80 as to occupy one-half of it, tlie remaining half being filled 

 with fragments of potash, A tube is adapted whicli is connected 



