280 Sdentijic IntdUgetice. 



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 certainly ; but 

 at the same time carbonic acid was disengaged, which it was requisite 

 to collect and estimate. For this purpose the current of air was di- 

 rected, at its exit from the tube, inio two vials containing 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 repre- 

 sented, was added to that obtained by the following 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 calcined resi- 

 due still contained a trace of it. To determine its amount, the authors 

 dissolved the residue in hydrochloric acid, and passed over the hot so- 

 lution 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 magne- 

 site contained, consisted of — 1, the portion removed 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 sufficient 

 care, and gave satisfactory results. The last eleven determinations, 

 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 hun- 

 dredths, the round number 250 may be adopted as the equivalent of 

 magnesium, that of oxygen being 100, or 20, taking the equivalent of 

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

 sia consist of 60 magnesium and 40 oxygen ; and 100 parts of carbon- 

 ate of rnagnesia are constituted of 47-619 carbonic acid and 52-381 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. 



3. New Metal, Donarinm, (Pogg. Ann,, vol. Ixxxii, April, 1851.)- 

 This new metal Donarium was obtained by Dr. Bergemann, while 

 experimenting on the VVohlerite and Eukolite of Brevig, Norway. 

 A mineral substance was separated, which has since been called 

 Orangite, which is essentially a silicate of Donarium, of the formula 

 Do^ 03, Si 03 4- 2H0, and affording on analysis 



Si Do,0 CaC Pe AfoASn filtt little JSTa fl 



lt-695 ^71-247 4-042 0-310 0-214 0*303 6-900=100-711 



The metal was obtained from the oxyd by means of potassium ; 't 



Wormed a heavy coal-black powder, which, when dry and rubbed in a 



mortar acquired a metallic lustre. It burns when thrown into the flanie 



of a lamp wuh a reddish light, and forms a red oxyd. Hydrochloric 



acid, hot or cold, has no action on the metal : and nitric acid only whea 



