DISEASES OF PLANTS. 841 



Forest products of Canada, 1913. — Lumber, lath, and shingles, R. G. Lewis, 

 \V. E. Dexter, and W. G. II. Bovce (DciJt. Int. Canada, Forestry Branch Bui. 

 ^S (1915). pp. 55, pi. 1).— This is the UKiial report (E. S. R., 30, p. 46) on the 

 quantities, kinds, and values of lumber, lath, and shingles manufactured in the 

 Dominion and in the various Provuices for the calendar j-ear 1013. The total 

 value for the year was $70,644,362, of which lumber represents $65,796,438. 



Tests of wood preservatives, 11. F. Weiss and C. H. Teesdale (U. S. Dept. 

 Agr. Bui. 145 (1915), pp. 20, pis. 6, fig. 1). — This bulletin describes experiments 

 conducted to determine the practical value as wood preservatives of some thirty- 

 compounds and chemiciils. The experiments were performed by E. Bateman. 

 C. J. Humphrey, Ruth Fleming, and R. E. Prince. The preservatives tested in- 

 clude coal-tar creosotes of various fractions, water-gas-tar creosotes, wood tar 

 and creosote, copperized oil, fuel oil, kerosene, zinc chlorid, zinc sulphate, 

 sodium silicate, sodium fluorid. and other preparations of similar nature listed 

 under trade names. 



The methods of conducting the tests are described and the results are pre- 

 sented in a series of tables. The data given show the physical and chemical 

 properties of the preservatives, penetrance of the preservatives and their effect 

 on the strength of wood, permanence of the preservatives after injection 

 into wood, inflammability of treated wood, toxicity of preservatives to Fames 

 annosuft and /'. pinicola, corrosive action of the preservatives, and discolora- 

 tion of wood treated with preservatives and painted. 



The experiment shows in general that highly viscous oils do not readily pene- 

 trate, while oils with low viscosities penetrate wood readily. To secure the best 

 results, both the wood and the preservative should be sufficiently heated during 

 the pressure period and the treatments should not be made too rapidly on 

 account of the low thermal conductivity of w^ood. With water-soluble salts 

 these precautious are not important. Judging from the toxic values secured in 

 this work there is, in practice, being forced into wood about one and one-half 

 times as much zinc chlorid and from ten to twenty times as much coal-tar creo- 

 sote as is necessary to prevent decay. It is believed that more economic results, 

 especially when decay is accompanied by mechanical deterioration, can be 

 secured by diffusing the preservative more thoroughly through the wood than 

 by saturating the outer fibers and attempting to retain in the wood the more 

 toxic volatile constituents through admixtures of nonvolatile constituents. In 

 the case of zinc chlorid the factor of safety is very low. To secure the best 

 results the injection of from 0.4 to 0.5 lb. per cubic foot now commonly used 

 should be increased. 



Wood treated with oils in every case ignited at lower temperatures than un- 

 treated wood. Prolonged seasoning of such wood, however, raises considerably 

 its ignition temperature. It seems advisable to season such treated timber 

 before placing it in positions subject to fire. Wood treated with water-soluble 

 salts was in general less diflicult to ignite than untreated wood, nevertheless the 

 presence of such preservatives usually renders the wood slow burning and easily 

 extinguishable. 



The results of the tests made indicate that woods treated with zinc chlorid, 

 sodium fluorid, and other water-soluble salts might be successfully painted. No 

 definite conclusions can be drawn in regard to this point until the results of 

 tests in cooperation with the National Paint Manufacturers' Association become 

 available. 



DISEASES OF PLANTS. 



Annual report of the botanical experiment station at Proskau in 1913, 

 R. EwEBT (Ber. K. Lehranst. Obst it. Gartenbau Proskau, 1913, pp. 135-150, 

 figs. 3). — The author notes that young Fertility peai* trees this year, as pre- 



