314- Intelligence and Miscellaneous Articles. 



oxygen, and the last two by combining with their hydrogen, on 

 account of the great affinity for it to form hydracids. — Journal de 

 Pharmacie, March 1831. 



PERCHLORIC ACID. 



M. Serullas has discovered that perchloric acid is obtained by 

 distilling chloric acid. The watery part is to be rejected as use- 

 less, and a colourless dense liquid is observed to adhere to the sides 

 of the vessel. When the heat is increased, and which ought to be 

 sufficiently strong to heat every part of the body of the retort, the 

 liquid passes into the receiver; this is perchloric acid: although 

 concentrated, it does not inflame paper like chloric acid, but it 

 gives to the paper, when put in contact with a red-hot coal, the 

 property of forming very vivid sparks. 



During the distillation of the chloric acid, chlorine and oxygen 

 separate, and a portion of the latter combining with the undecom- 

 posed chloric acid, it passes to the state of perchloric acid, which 

 is very permanent, and may be distilled at a high temperature with- 

 out any decomposition. The acid distilled has a light rose colour, 

 probably derived from a little manganesiate of potash contained in 

 the chlorate of potash; but on concentrating it by heat, it becomes 

 colourless. To be quite sure that the chloric acid is pure, it may 

 be redistilled. This process is much preferable to that of Count 

 Siadion, which is complicated, and also dangerous in the execution. 

 There remained some doubts as to the composition of perchloric 

 acid. M. Serullas has ascertained that it is composed of two atoms 

 of chlorine and seven atoms of oxygen. — Ibid. p. 142. 



RED SOLUTIONS OF MANGANESE. 

 The red colour of the sulphate of manganese procured under 

 certain circumstances, has been attributed to the presence of per- 

 oxide, deutoxide and red oxide. Mr. Pearsall is, however, of opi- 

 nion that it is caused by manganesic acid. Among other reasons 

 which he assigns for this opinion, are the following : the red solu- 

 tions of manganese and the solution of manganesic acid are both 

 alike in colour and in bleaching power ; both become colourless by 

 the same agents, and lose their bleaching power by losing their 

 coloured state; they are similarly affected by reagents, and afford 

 similar red crystallized salts: when deprived of colour they afford 

 a crystallized colourless proto-salt, and both are compatible with 

 certain other solutions of other substances.— Jou?-Ha/ of the Royal 

 Institution, Aug. p. 62. 



POWERFUL ELECTRO-MAGNET. 



Professor Henry and Dr. TenEyck have constructed an electro- 

 magnet for Yale College, which is stated to have sustained 2063 

 pounds. The magnet is wound with 26 strands of copper bell-wire, 

 covered with cotton thread, 31 feet long; about 18 inches of the 

 ends are left projecting, so that only 28 feet of each actually sur- 

 round the iron ; the aggregate length of the coils is therefore 



728 feet. 



