518 M. Carius on a New Method of Analysis. 



bonic acid at ordinary or higher temperatures, all the three forms 

 are obtained — chalk, calc-spar, and Arragonite. 



Calc-spar is formed under other circumstances. When a solu- 

 tion of bicarbonate of soda was precipitated with chloride of cal- 

 cium, and the milky liquid allowed to stand, rhombohedra with- 

 out Arragonite were obtained; but when chloride of calcium 

 was precipitated by neutral carbonate of soda, Arragonite only 

 was obtained. It appeared as if carbonate of lime only separated 

 as calc-spar when surrounded by an atmosphere of carbonic acid. 



To determine the limits within which the two forms are pro- 

 duced, the fused mass was gradually added to water at different 

 temperatures. The result was, that between 100° and 90° Arra- 

 gonite was almost exclusively formed : below that point, princi- 

 pally prisms of Arragonite and rhombohedra of calc-spar; at 

 70° the rhombohedra predominated, and laminae of calc-spar 

 appeared, and at 30° the formation of Arragonite ceased. The 

 limit to its formation appeared to lie between 50° and 30°. 



The author is still engaged with the subject. 



Carius has described* a new method of elementary analysis, 

 by which sulphur, phosphorus, and chlorine in organic bodies 

 may be determined. It consists in heating the substance in 

 closed tubes with nitric acid. 



The substance to be analysed is filled into small thin glass 

 bulbs which are sealed before the blowpipe. The bulb is then in- 

 troduced into a tube of about half an inch diameter sealed at one 

 end, and half-filled with nitric acid of sp. gr. 1*2. This tube is 

 then drawn out in the gas-flame, and, the nitric acid having been 

 raised to boiling, the tube is sealed. By careful management 

 the bulb is broken, and the tube then heated in a Bunsen's air- 

 bath. This consists of a rectangular sheet-iron or copper box, 

 about 14 inches long and 4 inches high ; in one end there are 

 two openings, which contain pieces of iron gas-pipe about an 

 inch wide and closed at one end. The tube to be heated is 

 placed in one of these pipes and loosely closed by a cork. The 

 bath is then heated by a Bunsen's burner, the temperature being 

 indicated by a thermometer. The advantage of this air-bath is, 

 that any possible explosion is quite harmless, provided the bath 

 be placed with the open end of the iron tube in the corner of a 

 room. 



After the oxidation is complete, which occupies a few hours, 

 the finely drawn out end of the tube is softened in the blowpipe 

 flame; it bursts and gives exit to the gaseous products without 

 any loss of the liquid. The sulphur is present in the liquid con- 



* Liebig's Annalen, October 1860. 



