124 



Selections. 



[NO. 5, NEW SERIES, 



The protective property of the coating formed on the wood, pre- 

 pared by this process, was not found to be considerable, while the 

 expense of the materials was great, as compared with others equal- 

 ly efficient. 



The successful results obtained on the Continent by the applica- 

 tion of alkaline silicates, as protective materials, led to an exami- 

 nation into the comparative value of the cheapest of these, the 

 1 soluble silicate of soda, as an agent for decreasing the combusti- 

 bility of wood. 



The property possessed by the soluble alkaline silicates, of being 

 readily softened by hot water, and thus converted into a state of 

 solution, while they are but slightly affected by cold water, renders 

 their application to wood, either in the form of a bath, or as a 

 wash, very simple. Their dilute solutions being readily absorbed 

 by wood the surfaces of the latter, as it dries, assume the form of 

 a hard coating. 



The experiments made in the first instance with the silicate of 

 soda, and the results obtained, are described in the following ex- 

 tract from the official report : — 



" Various specimens of dry wood were prepared with silicate of 

 soda, by being soaked for a few hours in a weak solution, 



" Upon examining the interior of these, after the removal from 

 the bath and subsequent desiccation, the silicate was found to have 

 penetrated about a quarter of an inch on all sides. 



" On piling the above over afire, together with specimens of un- 

 prepared wood, and others that had been prepared by different 

 processes, the superiority of the silicate of soda, as a protective 

 agent, was fully established. 



" Some specimens of wood were then simply painted with a 

 moderately strong solution of silicate, and afterwards placed, to- 

 gether with unprepared wood, in a pool of coal-tar naptha some of 

 the latter being thrown over the surfaces of the wood. 



Uupon the results of these experiments being reported, an or- 

 der was issued by Lord Panmuee to have the proposed process for 



