Processes for Wood-preservation. 193 



764. Incombustible Wood. Experiments have been made by order 

 of the English Admiralty, to test a process of Dr. Joues for render- 

 ing wood incombustible, by the use of the tungstate of soda, a salt 

 obtained by the action of muriatic acid and common salt upon the 

 tu upstate of lime (scheelite). Soft woods arc said to be rendered 

 solid and durable. 1 



71 i"). Ai.tm tends to render wood incombustible, and claims have 

 bi't-n asserted in favor of its antiseptic properties, while others have 

 found that it tends to hasten decay. The soluble nature of alum 

 would render it improper for use where exposed to the rains, but 

 its well-established properties for resisting ignition may render it 

 worthy of notice for inside work. 



Hit). Borax. It has been proposed to saturate wood with borax, 

 by immersing and gradually heating to a boiling point, and leaving 

 for half a day. The wood is then piled, and after a time again 

 boiled for less time in a weaker solution. It is claimed that this 

 renders wood less combustible, and the process does not discolor it. 



707. Lhni' appears to render wood durable, as we see in the boards 

 used for mortar-beds. M. Lostal, a French contractor, has proposed 

 to place wood in a large basin or receiver, and cover it with a layer 

 of fresh-buried lime, which is watered by degrees till it slacks. 

 Water is then let in till the wood is covered, and it is allowed to 

 stand for some time. It gives a hardness, and it is claimed a dura- 

 bility worthy of notice. It also tends to render wood less liable to 

 ignition. 



768. Sulphate of Iron. It is well known that copperas or green 

 vitriol will tend to increase the durability in woods, and the lasting 

 qualities of vessels engaged in the coal trade of England are attrib- 

 uted to the pyrites which all English coals contain, and which form 

 this salt by exposure to the air and to moisture. The pieces forming 

 parts of carriage-wheels and other wooden structures, when fitted 

 for putting together, are sometimes boiled three or four hours in a 

 solution of this salt, and then placed for some days in a warm place 

 to dry. It is not corrosive to iron, and nails driven into it will last 

 as long as the wood itself.* 



1 Revue des Eanx et Forefs, 1874, p. 302; 1875, p. 143. 



2 Prof. F. W. Clarke in noticing the disagreement in statements concern- 

 ing this substance remarks : "At all events, it has had less thoroughly than 

 soir.e other more fashionable preservatives, the test of long experience. It 



