33S REID ON THE ECONOMY OF TIMBER. 



Chemistry has furnished us with substances that possess this 

 property in a marked degree. Common Alum is very good. 

 Filling the pores of timber with Sulphate of Lime or Plaster of 

 Paris, by double decomposition, is also good. Tung state of Soda 

 is better than either, but its price militates against its use. Silica 

 either alone or combined with an alkali or alkaline earth, is the best 

 substance as yet known, and is most frequently used as Silicate of 

 Potassa, or Soda in solution. Fuch, of Munich, Bavaria, in 1823, 

 first made known the remarkable properties of these compounds and 

 used them as preservatives of stone from decay, and of wood from 

 fire and decay — and as well the best groundwork and fluid for the 

 Fresco Painter. The theatre of Munich was the first, edifice pro- 

 tected from fire and decay and ornamented also by these compounds. 



Pansome in England in 1845-56, patented the use of soluble sili- 

 ca for the making of an artificial stone, and the preservation of stone 

 and timber ; and it is at present largely used for these purposes. 



One of my objects this evening was to show the value of Silica, 

 — injected into the pores of the wood, when united with Soda or 

 Potassa, or decomposed afterwards by lime in solution, when so 

 introduced, and the saturation of the timber wath common salt at 

 the same time. Or by simple application of the solution to the 

 exterior, either alone or with clay, whiting, or Plaster of Paris, 

 which makes a cheap and effective fire paint. 



When injected into pine timber, and afterwards dried, I find it 

 is not difficult to increase the weight 50 per cent, and confer great 

 powers of indestructibility. It could be introduced with very 

 great facility into telegraph poles, wharf logs, and undressed 

 timber, by the method used for the introduction of Sulphate of 

 Copper into telegraph poles in England, viz : by hydrostatic 

 pressure. The fluid being elevated a number of feet above the 

 ground, and a tube connecting it with a cup, which by means of a 

 Caoutchouc connection is tightly secured around the large end 

 of the log, the sap of the timber is expelled and replaced by the 

 preservative. 



I will briefly summarize the advantages due to silicating timber : 



1- To prevent wet and dry rot. 



2. To increase the hardness and density. 



