748 Forestry Quarterly. 



The author proposes an improvement in this process by treat- 

 ing different species separately and in different times, namely, 

 7 days for pine, 10 — 14 days for spruce and fir. Also for dif- 

 ferent species, liquors of different strength should be used, and 

 that under vacuum and pressure which could be done by 

 employing concrete tanks or cylinders (since the poison corrodes 

 metal) and rubber tubing, etc, by which larger quantities could 

 be forced in. 



The cost of the process in spite of the high price of mercury 

 ($60 to $85 per 100 lbs.) is relatively small, for the quantity re- 

 quired in a 2/3% solution is not more than ^ to i ounce per cubic 

 foot and therefore the total cost per cubic foot 4 — 5 cents (about 

 12 to 15 cents per tie) for the material. 



Caution in handling the poison is necessary, but many of the 

 objections raised, the author thinks, are exaggerated. 



Creosote oil, which, as a waste product of the coal tar industry, 

 Bethell recommended in 1838, has constantly increased in use, 

 so that at present it is difficult to supply it and the price has risen 

 accordingly, and hence substitutes are sought for — phenols, cresols 

 — which may be artificially prepared. Creosote was objectionable 

 because originally such large quantities were apparently needed per 

 cubic foot and the smeary condition of the treated wood was ob- 

 jectionable. Newer processes have in part overcome these objec- 

 tions, Ruping's process (1902) being among the best. It consists 

 in admitting the liquor only after the wood has been under pres- 

 sure of two to four atmospheres for a quarter hour when the heat- 

 ed (75°C) oil is put in under pressure of 7 to 8 atmospheres; the 

 surplus of oil runs off when the pressure is removed. The con- 

 trol is indicated on a card like a steam pressure card. A series 

 of such cards illustrating the progress of the process and cuts of 

 treated ties to show the penetration accompany the text. This 

 process is superior to the chlor-zinc-tar oil process, being simpler 

 and easier to handle. 



Another patented process designed to save oil and distribute the 

 oil well is known as Rutger's patent, which treats the charge with 

 liot steam or hot air under pressure to prepare it for impregnation. 



This process used by the firm of Guido Rutgers is mainly used 

 for telegraph poles, the Austrian Telegraph Administration hav- 

 ing from 1904 to 191 1 placed some 300,000 poles treated in this 



