PROCEEDINGS OV THE THIRD ENTOMOM)GICAL MEETING 711 



thin liquid smelling of creosote. They were buried on 31st August 

 1916 and were untouched up to 31st July 1918, a period of 23 months. 

 They were reburied for further test, and this trial is therefore incom- 

 plete. 



Placing these various processes in order as regards efficacy, so far 

 as our experiments show this, we obtain the following results : — 



Months 



Creosote (hot), more than 81 



Creosote (cold), less than 28 



Carbolineum, less than •••■•... 23 



Powell Process, less than 21 



Lead Arsenate, less than 10 



Mortant, less than 15 



Sideroleum, less than ........ 14 



Microlineum, less than ........ 14 



Solignum, less than 12 



Zinc Chloride, less than 12 



Timborite, less than H 



Lead Chromate, less than ........ 7 



Siderosthen, less than 4 



There is also Orr's Wood Preservative which had lasted 23 months 

 on last examination (trial incomplete). As this is apparently a form 

 of creosote, it may be expected to do well. 



We do not think it necessary to state more than the bare facts, as 

 our conclusions are practically identical with those obtained at Dehra 

 Dun by R. S. Pearson and lately published in " A Further Note on the- 

 Antiseptic Treatment of Timber " (Indian Forest Records, Vol. VI, 

 pt. IV (1918)). It will be noticed, however, that treated wood at Pusa 

 has a considerably shorter hfe than at Dehra Dun and this is probably 

 due to a difference in the termite attacking it, the Pusa species being 

 Microtennes obesi and that at Dehra Dun (as ascertained by one of us 

 when at Dehra Dun in August 1918) a species of Odonfotermes, probably 

 0. obesus. 



Another point which is brought out in the Tables, is the fact that 

 treatment is of little use if the whole surface subject to attack is not 

 treated. If the wood is cut after treatment, so as to expose an un- 

 treated interior face, this latter is especially liable to attack, which may 

 then invade the interior of the wood. For examples of this see the 

 Table of experiments with Lead Arsenate, in which treatment was 

 effective in the case of whole pieces for 33 months whilst exactly similar 

 (but cut) pieces failed within 11 months. We have excluded such, 

 failures from the above table of durability. 



