212 Miscellaneous Intelligence, 



away by a current of hydrogen applied whilst the tube is heated, 

 and then pieces of potassium are introduced, and the tube being 

 again heated, their vapours are carried over the cliloride, which is 

 reduced more or less powerfully by the operation. The substance 

 obtained is to be rapidly washed in alcohol, of specific gravity 0.85, 

 to remove chloride of potassium, then pressed between paper, and 

 dried in vacuo. It is a rose, or chocolate-brown powder, containing 

 more or less oxide resulting from the action of the alcohol ; it gene- 

 rally resembles silicium in appearance ; it smells of hydrogen ; in 

 boiling water rapidly disengages hydrogen, and in cold water evolves 

 it also, but more slowly ; by friction it acquires a dull lustre ; it is 

 a non-conductor of electricity ; when heated in the air it takes fire, 

 long before the temperature has risen to redness, and burns vividly 

 into oxide ; heated with chlorate of potash, or with nitre, it deto- 

 nates violently. It does not combine with melted sulphur, but 

 burns in the vapour of sulphur ; it is not acted upon by phosphorus ; 

 it burns vividly when heated in chlorine. 



The sulphuret is best made by passing the vapour of sulphuret of 

 carbon over it at a red heat ; it is a red powder, having an appear- 

 ance between cinnaber and minium ; it may be made by heating 1 

 part of oxide of cerium and 3 parts of sulphuret of potash to red- 

 ness, for half an hour. 



Carburet of Cerium. — The oxalate of cerium is to be decomposed at 

 a moderate temperature, in a close apparatus, and the greyish-black 

 powder obtained digested in muriatic acid ; chlorine is evolved, 

 and a heavy brown-black powder deposited, which, being washed 

 and dried, is the carburet of cerium. Heated in the air, it burns 

 vividly into oxide of cerium, without any appreciable change of 

 weight. — Ann. der Phys. 1827, 406. — Bull. Univ. A. x. 64. 



22. JJseofChameleonMineralformarking Linen. — In many large 

 establishments linen requires to be marked quickly, permanently and 

 economically. The following is a process recommended in France : 

 Prepare a chameleon mineral, by heating a mixture of 1 part oxide 

 of manganese of commerce, and 2 parts of nitre, or common potash, 

 to redness ; the green substance obtained is to be preserved in dry 

 bottles, as it changes in the air. When required for use, it is to be 

 powdered, and mixed with its weight of pipe-clay, and then water 

 added, to make a very thin paste. It is this mixture which is to be 

 applied to the linen, either by a brush, or a stamp, or in the manner 

 of stencilling, or even by a pen, if it be made thin, and used quickly. 

 The green paste quickly changes to brown on the linen, and the 

 latter being washed about half an hour afterwards, the loose par- 

 ticles and the potash are removed, and the marks left of a deep 

 brown colour. This writing perfectly resists the action of alkaline 

 lixivia, even though strong ; it also resists soap and weak acids : 

 hence the process may be useful to calico-printers. The operation 

 depends upon the reduction of the manganesic acid in the chameleon 



