OF RENDERING PLATINA MALLEABLE. 
5 
sion, at an elevation of 5°, becomes nearly 60 X power, and at an elevation of 
1°, becomes nearly 300 X power ; and when the lever becomes horizontal, the 
multiplier of the power becomes quasi infinite. This explanation will be suf- 
ficient to show the mechanical advantage with which, by means of this press, 
the weight of the operator, acting on the end of the lever, will be made to 
bear against the area of the section of the barrel, a circle little more than an 
inch in diameter. 
After compression, which is to be carried to the utmost limit possible, the 
stopper at the extremity being taken out, the cake of platina will easily be 
removed, owing to the conical form of the barrel ; and being now so hard 
and firm that it may be handled without danger of breaking, it is to be placed 
upon a charcoal fire, and there heated to redness, in order to drive off moisture, 
burn off grease, and give to it a firmer degree of cohesion. 
The cake is next to be heated in a wind-furnace ; and for this purpose is 
to be raised upon an earthen stand about 2^ inches above the grate of the fur- 
nace, the stand being strown over with a layer of clean quartzose sand, on 
which the cake is to be placed, standing upright on one of its ends. It is then 
to be covered with an inverted cylindrical pot, of the most refractory crucible 
ware, resting at its open end upon the layer of sand ; and care is to be taken 
that the sides of the pot do not touch the cake. 
To prevent the blistering of the platina by heat, which is the usual defect 
of this metal in its manufactured state, it is essential to expose the cake to the 
most intense heat that a wind-furnace can be made to receive, more intense 
than the platina can well be required to bear under any subsequent treat- 
ment ; so that all impurities may be totally driven off, which any lower tem- 
perature might otherwise render volatile. The furnace is to be fed with Staf- 
fordshire coke, and the action of the fire is to be continued for about twenty 
minutes from the time of lighting it, a breathing heat being maintained during 
the last four or five minutes. 
Th’e cake is now to be removed from the furnace, and being placed upright 
upon an anvil, is to be struck, while hot, on the top, with a heavy hammer, so as 
at one heating effectually to close the metal. If in this process of forging, the 
cylinder should become bent, it should on no account be hammered on the 
side, by which treatment it would be cracked irremediably ; but must be 
