96 Tungsten. — Stencilling. 



litanium, obtained by decomposing the gallate of that metal 

 by potash or soda. The metalhc titanium is of a dark 

 copper colour, has much brilliancy, is brittle, but possesses, 

 in small scales, a considerable degree of elasticity : it tar- 

 nishes on exposure to the air, 'and is easily oxided by heat, 

 which gives it a blueish aspect : it detonates with nitrate of 

 potash and is highly infusible. All the dense acids act upou 

 It with considerable energy. 



TUNGSTEN. 



Richter, the German chemist, has published the follow- 

 ing method of obtaining tungsten : 



Expose equal parts of tungstic acid* and dried blood for 

 some time to a red-heat in a crucible; put the black powder 

 which is formed into a smaller crucible, and expose it again 

 to a violent heat in a large lire for at least an hour. The 

 result is tungKtcn in its metallic stale. 



STENCILLING. 



On this process, which is employed in different manu- 

 factures, we have received a communication from Mr. T. 

 Gill, which we think furnishes a very useful hint, and may 

 possibly lead to an extension of the use of stencils : 



*' Wishino-," says he, *' to pnjduce some copies of a 

 miniature profile, lately taken by Mr. Hawkins's patent 

 method (viz. by a machine, which being traced over the face 

 itself, at the same time draws the outlines of the profile oit 

 a reduced scale), which was cut in thin wove post paper; I 

 coated it prettv thick on both sides with the cement No. xvii. 

 described in the Philosophical Magazine, vol. xiv. p. 122; 

 which dried instantly, and rendered it perfectly impervious 

 to oil and water, and sufliclcntly stiiT. In short, the paper 

 became a very excellent stencil, with which I was enabled 

 to multiply the profiles with as much facility as if it had 

 been a brass impression plate. I think the above informa- 

 tion may be useful to manufacturers of paper hangings, 

 cards, floor cloths, and in short to all who employ stencils, 

 as a method of preparing them, far superior to that in gene- 

 ral use ; which consists in coating them with boiled linseed 

 oil, as the. oil. requires much time to become dry, and, I be- 

 lieve, woukl never render the stencil so firm and durable, as 

 by this new process." 



•^ Or more pFo;jerly tungnic oxide; tungsten, by some late experiments, 

 appearing not to be acidii'iable. 



