KUKAL ENGINEERING. 789 



perature between 160 and 175° C. The penetration of the objects by the gas 

 was found to begin in about 3 hours after commencing the exposure. 



Disinfection for all practical purposes can be attained in from 5 to 7 hours 

 for all room and general superficial purposes, but books and mattresses require 

 24 hours at a temperature of from 18 to 28°. The gas is absolutely efficient 

 under these conditions for destroying Bacillus typhosus, B. diphtheria;, and the 

 staphylococcus, but is not certain with spores, particularly the spores of B. 

 subtilis. Disinfecting rooms, books, mattresses, etc., at a temperature below 

 10° is not possible. At from 10 to 18° it is just apparent but rather inconstant, 

 while from 18 to 30° the penetration is absolutely efficient for rooms, carpets, 

 and most other objects. Perfect disinfection of mattresses and books can be 

 secured at 50 to 60°. 



The effect of certain reagents on hides, W. F. Cooper and W. H. Nuttall 

 {Jour. Econ. Biol., 5 {1910), No. 4, pp. 157-159).— The authors state that the 

 application of picric acid, pyridln picrate, and mercury bichlorid does not inter- 

 fere with the tanning process or affect the color of the tanned pelt. "As far 

 as any objection to tanning is concerned, there is no reason why a large num- 

 ber of other dyes and chemicals should not be tried as a means of controlling 

 and preventing . . . infestations by many pests." 



RURAL ENGINEERING. 



Second progress report of cooperative irrigation investigations in Cali- 

 fornia, F. Adams {U. S. Dept. Agr., Office Expt. Stas. Cire. 108, pp. 39).— This 

 circular continues the report of the irrigation investigations carried on by the 

 Office and the State of California (E. S. R., 16, p. 9.30). It discusses the water- 

 right situation in California, including recent legislation in other States and 

 needed changes in California, describes the present status of irrigation de- 

 velopment in the State, and reports duty of water determinations, investigations 

 of irrigation by pumping, studies of water distribution and delivery, the use of 

 concrete in irrigation, the application of water to crops, seepage losses from 

 canals, the cleaning of canals, the drainage of irrigated lands, and the status 

 of investigations now under way. 



In experiments to determine the duty of water on various standard crops in 

 the State at large it was found that the duty on alfalfa varied from 1.40 ft. 

 to 8.60 ft. On citrus fruits in southern California the duty varied from 0.80 ft. 

 to 2.48 ft. 



On the experiment farm at Davis 8 plats of alfalfa which received no irri- 

 gation yielded 4.08 tons per acre, while 22 plats which received 12, 24, 30. 36, 

 and 48 in. of water yielded respectively 4.79, 6.43, 8.09, 7.60, and 8.45 tons per 

 acre. Experiments in irrigating barley and corn showed large increases in 

 yield with the application of relatively small amounts of irrigation water. 



Complete tests were made of 38 pumping plants in the vicinity of Pomona 

 and Riverside and fuel and water tests of 100 others. The complete tests 

 showed that the efficiency of the gasoline-driven plants varied from 30 to 50 

 per cent and that of electrically-driven plants from 40 to 55 per cent. The 

 partial tests showed a greater economy in fuel consumption in the larger than 

 in the smaller plants and a striking variation in fuel consumption in the 

 different plants. 



Measurements of seepage losses from canals showed that the losses varied 

 from 0.17 to .51.50 per cent per mile, and averaged 5.93 per cent. 



Irrigation investigations at Koppenhof, 1910, E. Kruger {Mitt. Kaiser 

 Wilhelms Inst. LamUv. Bromberg, 3 {1911), No. 3, pih 115-183, pi. J).— From 

 results of experiments on fertilized and unfertilized fields planted to potatoes, 

 the author draws the following conclusions : 



