556 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



manganatcs and permanganates of potassa, soda, and baryta, ferrates 

 of potassa, soda antl barvta, chromates of potassa, soda and baryta, 

 and generally all metallic oxides or acids which will form with 

 potassa, soda or l^aryta binary compounds capable of superoxydis- 

 ing, possess the property of yielding their oxygen, at a more or 

 less elevated heat, when they are submitted to the action of steam. 

 Such bodies when deoxj^dized will l)ecome reox3'dized when ex- 

 posed to a current of he;ited air. The apparatus of the patentees 

 consists of a retort in which by the application of a current of air 

 to any of the compounds before mentioned they are brought to 

 the maximum state of oxydation. They are then deoxydized by a 

 current of steam or by injecting water; the oxygen and steam pass 

 from the retort into a condenser where the steam is condensed to 

 water and the oxygen is collected in a gas-holder. When the 

 compounds in the retort have given off a portion of their ox^^gen 

 they are again subjected to the action of air, and afterwards to 

 steam or water, and thus by this continued alternation the same 

 materials continue to supply oxygen as long as required. 



The process is said to Avork with great regularity, and will 

 doubtless be of great value in metallurgical operations. Oxj'gen 

 had been obtained previously from permanganates by the action of 

 heat, and these were afterwards sui)jected to air and rcoxydized, 

 but the patentees, by the use of steam as a heater, have succeeded 

 in deoxydizing a large class of compounds which may be rcoxy- 

 dized by common air. 



Tetra Chloride of Carbon or Arod. 

 Mr. Charles Crump, of Yealpton, 'England, has patented a pro- 

 cess for preparing C CI4 or Arod. He dissolves a small quantity 

 of iodine or of bromine with bisulphide of carbon, (^are^s). Dry 

 chlorine gas is then passed into this solution as long as it is ab- 

 sorbed, or until crystals of chloride of iodine [avad) begin to 

 appear. The compound thus formed is a mixture of tetrachloride 

 of carbon [arod) and sub chloride of sulphur [asad); it is digested 

 with sulphur 1)}^ which asad is converted into asod. Afterwards 

 arod is partially separated by distillation and treated with a solu- 

 tion of lime or potash, or similar material, for its purification. 



New Test for Iodine. 

 M. Carey Lea, of Philadelphia, has published in Silliman's Jour- 

 nal a new method of detecting very minute quantities of iodine. 



