516 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



perfectly protected from moisture; the paraffine would not 

 be displaced by diffusion, in consequence of the moisture of 

 the earth ; the iron spikes would not become loose ; the elas- 

 ticity of the wood would not be impaired ; the waste of the 

 impregnating solution would be small, and any refuse of the 

 finished ties thus treated would have increased value as fuel. 

 The chief difficulty with the process lies in the thorough 

 drying of the wood. By using crude paraffine the process 

 would be cheap, and light hydrocarbons might be used as 

 solvents. Apparatus adapted to the purpose might consist 

 of a wrought-iron cylinder, to receive the wood, capable of re- 

 sisting a pressure of fifteen atmospheres, and to be heated by 

 passing high-pressure steam through a jacket around it. The 

 drying of the wood could be completed in this way, and the 

 impregnating solution be forced in by action of condensed air 

 from a suitable reservoir, and then boiled by passing steam 

 through the jacket until a gauge indicates a pressure of seven 

 to eight atmospheres. The liquid, after cooling, may drain 

 back into the reservoir, the residue be distilled off through a 

 worm into the reservoir, air be forced into the impregnating 

 cylinder, and the wood removed. 16 (7, vi., 6 and 7, 90. 



VALUE OF THE EUCALYPTUS. 



Much attention has of late been given to the various spe- 

 cies oi Eucalyptus^ on account of their value as timber, and 

 as furnishing important vegetable products. Among the va- 

 rieties one known in Western Australia as the jarrah is espe- 

 cially useful, on account of the resistance of its timber to the 

 attacks of the white ant or the sea-worm. For this reason it 

 has come greatly into use for railway purposes, ship-building, 

 and dwelling-houses, especially in tropical countries. Com- 

 panies have been formed in Victoria for the working of these 

 trees, and arrangements are made for procuring the timber 

 and shipping it to any desired extent. 17^, May 1, 182, 262. 



KEPOET OF THE SUTEO TUNNEL COMMISSION. 



The report of the Sutro Tunnel Commission is printed in 

 detail, as an appendix to the report of the Chief Engineer of 

 the army, just issued. The commission consisted of General 

 H. G. Wright, General J. G. Foster, and Mr. Wesley Newcomb, 

 civil engineer, who gave the subject a thorough examination. 



