486 Miscellaneous Intelligence. 



the chlorides of lime at different periods. Welter's chloride at 

 100°, or full strength, consists of 18 atoms of chlorine, 36 of 

 water, and 36 of lime. This, when it becomes the dry chloride 

 of 66°, as before mentioned, consists of 12 atoms of subchloride of 

 lime, 5 of chloride of calcium, 1 of chlorate of lime, 6 of hydrate 

 of lime, and 6 of water. When this is dissolved in water, IS atoma 

 of lime separate, and there remain in solution 5 atoms of chloride 

 of calcium, 1 of chlorate of lime, and 12 of neutral chloride of 

 lime. The latter being evaporated, is converted into 1 atom 

 chlorate of lime, and 17 chloride of calcium. 



A solution of chloride of lime, out of contact of the atmosphere, 

 Undergoes a slow change at common temperatures, whether in 

 the light or dark, and pure oxygen is evolved, chloride of calcium 

 being formed. The same change takes place with chloride of 

 lime ; exposed to the air, it becomes converted entirely into chlo- 

 ride of calcium, atom for atom, evolving oxygen proportionate to 

 the chlorine present. This effect differs from that produced by 

 heat, when one-third of the chlorine forms chloride of calcium 

 and chlorate of lime. 



Manufacturers should be careful to make their bleaching powder 

 at as low a temperature as possible. In summer it is almost im- 

 possible to avoid the injurious evolution of heat. In winter it is 

 less difficult, but the operation should be always conducted in a 

 place as cool as possible, or one-third of the chlorine will be lost. 

 From the effects of heat, and of excess of lime or water in the 

 hydrate, bleaching powders of very low value are often sent into 

 the market even below 50°. The chloride shouid always be pre- 

 served in well- closed vessels, and in a cool place, that the spon- 

 taneous change may be retarded as much as possible, and the 

 contact of air, which is injurious, by giving water as well as car- 

 bonic acid, be prevented. — Annates de Chimie, xxxvii. 139. 



17. On a Gaseous Fluoride of Manganese, by M. Wohler. — Ordi- 

 nary chameleon mineral was mingled with half its weight of pow- 

 dered fluor sparj and acted upon by sulphuric acid an instant dis- 

 engagement of purple red vapours in large quantity took place. 

 The same experiment was made in a platina retort, and the gas 

 conducted into a platina crucible containing a little water ; it was 

 absorbed, and the water acquired the purple colour of manganese, 

 ■and was acid in properties. On opening the retort before the ac- 

 tion was over, it was found filled with a yellow gas, instantly 

 turning purple by contact with the air. To prove that the yellow 

 gas did not arise from nitre, a pure crystallized manganesiate of 

 potash was made by heating to dull redness equal parts of hydrated 

 potash and peroxide of manganese. This, mixed with its weight 

 of powdered fluor spar, free from silica, was acted on by sulphuric 

 acid as before, the gas passed first into a glass receiver and from 

 thence into water. For the first moment the receiver was filled 



