NOTES AND ABSTRACTS. 



137 



which forest fires may be subdued, either with or without water, while 

 the illustrations of beating out fires and the appliances used are well 

 reproduced. Altogether this is a valuable contribution to the subject 

 of which it treats.— .4. D. W. 



Forests, Some Insects injurious to. By A. D. Hopkins {U.S.A. 



Dep. Agr., Bur. Entom., Bull. 58, pt. v.; Dec. 1909).— The prin- 

 cipal insect enemies of Northern forests are described and their depre- 

 dations estimated at an annual loss of $100,000,000. Methods of 

 prevention and control are touched upon. — F . J. G. 



Fowl Manure {Jour, of Agr. Vict., p. 655; Sept. 1911). — The 

 fresh manure contains : Water 56 per cent. , organic matter 25 per cent. , 

 nitrogen 1 to 2 per cent., phosphoric acid 1.5 to 2 per cent., potash 

 0.8 to 0.9 per cent., lime 2 to 2.5 percent., magnesia 0.75 per cent. ; 

 it contains all plant foods and is worth about 25^. per ton. — C. H. H. 



Frost Figrhting- Studies in the Roque River Valley, Prelimi- 

 nary. By C. I. Lewis and F. E. Brown {U.S.A. Exp. Stn., Oregon, 

 Bull. 110, Aug. 1911; 19 plates).— The local branch of the U.S. 

 Weather Bureau, the telephone companies, and frost alarms are all 

 used to warn fruit-growers when the temperature reaches the danger 

 point. Two grades of oil were used in the experiments, and two 

 types of heaters. At 30^ F. outside temperature no increase was 

 obtained in the temperature of the orchard when twenty heaters to the 

 acre only were used, but with thirty-nine heaters to the acre an average 

 increase of 1^ was obtained, and with 100 to the acre ^^-^^o when the 

 heaters w^ere set 21 feet apart each way (p. 36). The average cost 

 for each acre for a period of four hours was $5.10 for oil, not counting 

 the equipment, and for wood under the same condition $ 5.40, as more 

 labour was required. Under the conditions experienced this season 

 there is considered to be no doubt that a crop can be saved by orchard 

 heating (p. 62). 



Observations lead the authors to doubt if an arbitrary table of tem- 

 peratures for frost injury can be made, as the humidity of the air and 

 the weather conditions generally seem to cause a very wide variation 

 in the effect of the frosts (p. 60). The failure of * Winter Nelis ' pears 

 to set was ijivestigated wuthout any conclusive results, though it was 

 thought to be due to the kind of weather which prevailed during; the 

 flowering period (p. 59). — A. P. 



Frost, Notes on. By E. B. Garriott, revised by A. G. McAdie 

 {U.S.A. Dep. Agr., Farmers' Bull. 104, Dec. 1910; 4 figs.).— This 

 gives the average dates of first killing frosts in autumn and last killing 

 frosts in spring at Weather Bureau stations throughout the United 

 States, w^ith devices for preventing rapid radiation of heat from the 

 soil and adding heat and moisture to the air with a view to protection 

 from frost. See abstract under " Orchards " in the E.H.S. Jouenai. 

 for November 1910 (vol. xxxvi., p. 505).— A, P, 



