Preservation of Aline Timbers 313 



corrosive sublimate, has been used only to a limited extent in 

 mine construction in Germany and Austria. The reason for this 

 must be looked for in economic conditions. It has been very 

 conveniently asserted that treatment with corrosive sublimate 

 brought with it fears for the mining industry, since the handling 

 of timbers treated with poison is dangerous ; the salt evaporates 

 into the air, and by precipitation the salt would appear in the 

 ground water and animals and men drinking it would be poi- 

 soned. Now as far as handling is concerned it will be readily 

 agreed that a process, by which since the year 1830 almost a 

 million poles have been treated in Germany without any cases of 

 poisoning whatsoever affords proof which does not admit of dis- 

 cussion by sane people. The evaporating belongs in the realm 

 of fable — chemists have no knowledge of it. The last point also 

 can be passed over in a few words. In general, mine waters are 

 not drinking waters, and, even if they were drunk, the minute 

 traces of corrosive sublimate which could reach them would be 

 entirely negligible. 



Heretofore wood has been treated with corrosive sublimate by 

 soaking it for a few days in a .06G per cent solution in open tanks, 

 but a better and more effective treatment is that in closed cylin- 

 ders under pressure. But under the influence of the corrosive 

 sublimate, as in the case of copper sulphate, the iron cylinders 

 suffer severely and are soon destroyed. To avoid this, coatings 

 of asphalt, tar, white lead, etc., have been tried extensively, but 

 so far have always resulted in failure. The only solution is 

 oflFered by the use of our newest building material, reinforced 

 concrete (Bisenbeton). Cylinders for the treatment with cor- 

 rosive sublimate under a pressure of up to as much as 8 atmos- 

 pheres are now made by concrete firms. 



The following may be enumerated as the most important fac- 

 tors in a preservative treatment: 1. Economy. 2. Effectiveness. 

 3. Permanence. 4. Undesirable accompaniments. 



The effectiveness can be looked upon as the keynote for every 

 system of preservative treatment. In forming an estimate of the 

 effectiveness (for which it was first necessary to conduct for 

 many years experiments in practice and in the laboratory), only 

 the work of independent, non-partisan investigators can have any 

 systematic value. Among the best, as far as effectiveness is con- 

 cerned, are, of the older methods, the treatments with zinc chlo- 



