242 EXPERIMENT STATION EECORD. 



A visual method for determining the penetration of inorganic salts in 

 treated wood, E. Bateman {U, 8. Dcpt. Agr., Forest Serv. Circ. 190, pp. 5, 

 fig. J). — To determine the penetration of zinc chlorid the freshly cut surface 

 of a representative disk of the treated wood is dipped in a 1 per cent potassium 

 ferrocyanid solution sufficiently long (not more than 10 seconds) to moisten 

 the entire surface. The excess of the solution is removed from the face by 

 blotting paper, the disk is dipped into a 1 per cent solution of uranium acetate, 

 and allowed to dry. On di'ying the untreated portions will have a dark red or 

 maroon color, while the treated portions will be slightly whiter than the 

 uatui'al wood, owing to the decolorizing action of soluble zinc salts on uranium 

 ferrocyanid. The test can not be used on red oak because the natural color 

 of the wood masks that of the uranium compound. 



This test is capable of detecting the presence of zinc chlorid in treated wood 

 in amounts as small as 0.17 lb. of the salt per cubic foot of wood. 



In testing for salts of copper, it is only necessary to dip the disk in the 

 solution of potassium ferrocyanid, the presence of copper being shown by a 

 dark red coloration in the treated zone. With salts of iron the same reagent 

 gives a deep blue coloration. The penetration of mercuric chlorid can be deter- 

 mined by treating a specimen disk with a solution of hydrogen sulphid, a black 

 precipitate of mercuric sulphid being formed. 



Forest products of Canada, 1910. — Cross-ties purchased, H. R. MacMillan 

 and W. G. H. Boyce (Dept. Int. Canada, Forestry Branch Biih 21, 1911, pp. 8). — 

 The number and cost of iwles used during the year are classified by species and 

 by length classes. The prices of poles in Canada and the United States are 

 compared and the possibility of treating the poles with creosote and other 

 preservatives is briefly discussed. 



The total number of wooden poles purchased in Canada during 1910 was 

 782,841, or an increase of about 118 per cent over the previous year. 



Forest products of Canada, 1910. — Cross-ties purchased, H. R. MacMillan 

 and W. G. H. Boyce (Dept. Int. Canada, Forestry Branch Bui. 22, 1911, pp. 

 7). — There were 9,213,962 cross-ties purchased in 1910 by the steam and electric 

 roads of Canada. The production by species and method of manufacture are 

 indicated and the preservation of railway ties is briefly discussed. 



Forest products of Canada, 1910. — Timber used in mining operations, 

 H. R. MacMillan, B. Robertson, and G. Boyce (Dept. Int. Canmla, Forestry 

 Branch Bui. 23, 1911, pp. 12). — A statistical summary showing the amount of 

 round and sawed timber used in the mines of the Dominion and of the several 

 Provinces during the year, giving also the quantity of wood of the different 

 species. About 52,848,000 linear feet of round timber and 22,305,000 ft. b. m. 

 of sawed timber were used for mining purposes in 1910. 



DISEASES OF PLANTS. 



The rational and efficient treatment of plant diseases in agriculture and 

 horticulture, E. Bourcart {Lcs Maladies des Plantes, leur Traitement Raisonn6 

 ct Efficaee en Agriculture et en Horticulture. Paris, 1910, pp. VI+655, figs. 

 H). — ^Accounts are given of the various substances that are used as fungicides 

 and insecticides, and their properties, metliods of preparation and use. and 

 effect on host plants and parasites are described. The various fungus diseases 

 and insect pests are enumerated in alphabetical order, and such descriptions 

 are given as will aid in their easy recognition. 



The galls of plants, E. Kijster {Die Gallcn dor Pflanzen. Lcipsic, 1911, pp. 

 A'+437, figs. 158). — This is a text-book for botanists and entomologists, in 

 which the author gives a general survey of the subject of plant galls and 



