Chemical Notices : — On tlie Artificial Formation of Minerals. 515 



Before concluding, I may be permitted to take the opportunity 

 of briefly stating another analogous problem that may possibly 

 interest some of the numerous readers of the Journal : — 



Sixteen symbols may be arranged five times in the form of a square, 

 so that every pair of symbols shall appear once both in a hori- 

 zontal and a vertical line. 



If not hereafter anticipated, I may take a future opportunity 

 of communicating a discussion of this neat problem. 



Alwyne Lodge, Canonbury, 

 Novembers, 1861. 



LXVI. Chemical Notices from Foreign Journals. 

 By E. Atkinson, Ph.D., F.C.S. 



[Continued from p. 309.] 



THERE are certain substances existing abundantly in nature, 

 such as hydrogen, fluoride of silicon, and carbonic acid, which, 

 without becoming fixed on the substances with which they come 

 in contact, change them into mineral substances identical with 

 those occurring in nature. These agents Deville* calls minera- 

 lizing agents, and in a series of experiments has shown that hy- 

 drochloric acid constitutes one. If sesquioxide of iron be heated 

 to dull redness in a porcelain tube, and a rapid current of hydro- 

 chloric acid passed through it, sesquichloride of iron is condensed 

 on the cooler parts of the apparatus, and water escapes along with 

 the excess of acid. But if the current is slow and regular, the 

 sesquioxide is changed into crystals quite identical in form with 

 those of specular iron ore ; at the same time as much hydro- 

 chloric acid escapes as enters the apparatus, not a trace of water 

 being formed. If the temperature is very high, the crystals have 

 the same form and the same angles as those of Elba iron ore; 

 while if the temperature is lower, the crystals resemble volcanic 

 specular iron ore. 



Deville has also prepared f artificial cassiterite and rutile by 

 the same method. Amorphous oxide of tin, obtained by the 

 action of nitric acid on tin, is placed in a platinum tray which is 

 heated in a porcelain tube to the fusing-point of copper, while 

 a slow current of hydrochloric acid is transmitted through the 

 tube. The oxide of tin remains behind in small but well-defined 

 crystals, identical in form with those of the native mineral. 

 When the current is rapid, a small quantity of bichloride of tin 

 is formed, which is transported to the further end of the tube; 



* Comptes Rendus, June 1861. % Ibid. July 22, 1861. 



