150 Chemistry and Chemical Arts. 
One hundred of these sticks are placed side by side, upon the mar- 
ble table, but without touching. When two men take an iron frame 
upon which a plate of iron heated to redness is placed, which they 
pass backwards and forwards at a little distance above the wax, and 
in less than a minute, the whole number of sticks receives a polish on 
one side. ‘They are then polished in the same way on the other 
side. The method of marking is so simple that it can be done by 
children. ‘The part of the stick to be marked is held over the high 
chimney of an Argand lamp, and when softened, is placed upon a 
support, where the impression is given by a little lever press. 
The qualities demanded in sealing wax are, to remain inflamed 
without dropping for some time, so as not to oblige us to hold the let- 
ter too near to the candle. It isnecessary also, after having inflamed 
the stick, that we have time to bring it over the letter, without the 
drops falling, that the wax remain fluid upon the paper long enough 
to enable us to spread it with the stamp, and to remove the coating 
of black smoke, which at first covers the fluid mass.* All these 
qualities are united in this sealing wax, besides which it sells for five 
francs the pound, while that of others costs eight to ten francs. —Idem. 
Avril, 1834. 
31. Filtration, (Journ. de Pharm. t. 19. p. 281.)—When a pow- 
der saturated with a fluid, but not in the condition of a paste, is pla- 
ced in the lower part of an open vase, and another liquid poured upon 
it, the last liquid permeates the powder and completely replaces the 
first, without mixing with it. ‘This substitution is mdependent of the 
specific gravities of the fluids; thus water drives out alcohol and 
wine, and alcohol and wine drive out water.—Ann. des Mines, t. 5, 
p: 376. 
32. Purification of Water.—In order to precipitate the earths 
mechanically suspended in water, it is recommended to employ the 
silicate of potash, gelatinous silica or phosphoric acid. ‘The last is 
an excellent reagent for throwing down the oxide of iron, without 
introducing any foreign principle into the water.—Jdem. 
* It has been remarked, that the older the wax grows, the less prone is it to pro- 
duce this black pellicle, a circumstance no doubt, depending upon the evaporation 
of the turpentine from exposure to the air. 
