Intelligence and Miscellaneous Articles. 309 



is the newer process less complicated and expensive, but I have 

 never yet found tartaric acid free from lime, and this base remains 

 combined with the titanic acid. If during the treatment of the tita- 

 niferous iron by the sulphuretted hydrogen the heat is not very 

 strong, the titanic acid obtained will render the washings milky, and 

 will partly pass through the filter ; but this will not occur if the heat 

 be sufficiently great. 



Hydrogen gas does not succeed so well as sulphuretted hydrogen : 

 the oxide is indeed reduced, but the titanic acid obtained by this 

 process is always ferruginous. Muriatic acid does not give a better 

 result. 



The time occupied in the operation now described may be short- 

 ened by fusing the titaniferous iron with sulphur in an earthen cru- 

 cible. The mass is to be treated with concentrated muriatic acid, 

 which removes much of the iron ; but some remains with the titanic 

 acid, and nearly as much as in rutile ; by treating this impure acid 

 with sulphuretted hydrogen as above described, it is obtained pure 

 at one operation. — Annates de Chimie, xxxviii. 133. 



ARTIFICIAL FORMATION OF UREA. BY M. F. WOHLER. 



M. Wohler has already shown, that when cyanogen is made to 

 act upon solution of ammonia, there are obtained, besides several 

 other products, oxalic acid, and a white crystalline substance, which 

 occurs also whenever the attempt is made to combine cyanic acid 

 with ammonia by double decomposition. On prosecuting his in- 

 quiries, M. W. found that by the combination of cyanic acid with 

 ammonia, urea was formed ; this is a remarkable fact, as offering the 

 artificial formation of organic matter, and even animal matter, by 

 means of inorganic principles. 



The white crystalline substance is most readily obtained by de- 

 composing cyanate of silver by a solution of muriate of ammonia, 

 or cyanate of lead by liquid ammonia ; it is colourless, transparent, 

 and crystallizes in the form of small rectangular quadrilateral prisms 

 without any distinguishable pyramids. Neither potash nor lime 

 evolves any trace of ammonia from this substance. Acids do not, as 

 with the cyanates, disengage either carbonic or cyanic acid: it does 

 not, like the cyanates, precipitate the salts of lead and silver ; it is 

 therefore evident that it contains neither ammonia nor cyanic acid. 

 Most acids have no marked action on this substance, but the nitric 

 acid when added to a concentrated solution gives a precipitate in 

 the form of brilliant scales. These crystals are extremely acid, and 

 were at first supposed to be a peculiar acid, but when decomposed 

 by bases, nitrates of those bases were obtained ; and by alcohol, 

 the white crystalline matter was obtained unchanged in its proper- 

 ties : these properties, when compared with those of pure urea ob- 

 tained from urine, indicated that this substance, or cyanate of am- 

 monia, is absolutely identical with urea ; a conclusion which is 

 strengthened by the properties assigned to urea in the writings of 

 Proust, Prout, and others. M. Wohler states some facts with re- 

 spect to urea (and also with regard to this artificial substance, ) which 



he 



