AGRICULTURAL ENGINEERING. 933 



Biennial Report of the Department of Highways of the State of California, 

 1903-4 | Bien. Rpt. Dept. Highways California, 1908-4, pp. 34, pis. 2).— This report 

 summarizes the status of road improvement in various counties 'of the State? giving 

 special attention to the use of cheap asphaltic oil roads which now cover over 2,000 

 of the 45,000 miles of roads in California, and the use of which has increased the 

 activity of the various counties of the State in the improvement of their roads. 



It is shown that about $2,000,000 are now spent annually in the State for highway 

 work. The form of a law which closely resembles the New York State aid law, and 

 which is recommended for enactment by the California legislature, is given. 



Oiled roads of California (California I>rj>t. Highways Bui. 2, pp. 41, figs. 5; 

 reprinted in Engin. Rec, 50 (1904), Nos. 23, pp. 663-666; 25, pp. 709-7 11; 26, pp. 752- 

 754; 27, pp. 780-783). — "It is the purpose of this bulletin to present all the available 

 data relative to oiled roads in California, and also to show the results obtained by 

 the application of crude oil to the various soils and roadbeds within the State." 



The experience of 40 counties, extending from Tehama in the north to San Diego 

 in the south, is summarized and deductions are drawn from the data "which will 

 give a basis of work to those desiring to enter upon or to continue this important 

 improvement to the highways of the State." 



Contributions from the agricultural machine and implement testing sta- 

 tion, Halle (Ber. Physiol. Lab. Landw. Inst. Halle, 1903, No. 17, pp. 1-61, figs. 48).— 

 Brief illustrated accounts are given of tests of a large number of agricultural machines 

 and implements, including hoof shears* harrows, mowing machines and attachments, 

 plows, potato diggers, brakes and couplings, machine weeders, milk separators, hay 

 rakes, and beet harvesting machine. Some account is also given in each case of the 

 methods of testing the efficiency of the different machines and implements. 



Appliances and methods used in testing agricultural machines, A. Nacht- 

 weh (FiMing's Landw. Zlg., 53 (1904), Nos. 1, pp. 19-21; 3, pp. 94-103, Jigs. 13; 6, 

 pp. 222-227, figs. 4; S, pp. 303-311, figs, 6; 11, pp. 418-422, figs. 2). 



Tests of grain pressure in deep bins at Buenos Ayres, Argentina, E. Lufft 

 (Engin. News, 52 (1904), No. 24, pp. 531, 582, figs. 7). — The results of observations 

 on circular bins 54.8 ft. deep and 11 ft. 3 in. and 23 ft. 10 in. in diameter, with a 

 special form of pressure gage, are reported. 



In the design of the pressure gage, which is quite similar to that described by 

 J. A. Jamieson (E. S. R., 15, p. 935), " the leading idea was to replace a small section 

 of the bin wall by a flexible rubber surface, so that the grain pressure could act 

 through this surface upon a counterbalancing column of fluid, as, for example, a 

 mercury column. . . . The pressure gage comprises a cast-iron body or pressure 

 chamber, open <m one side, which side is then covered over by a thin sheet of rub- 

 ber. This pressure chamber is embedded in the bin wall in such a manner that the 

 surface of the rubber membrane falls in the plane of the bin wall. 



"Care was taken, in putting the membrane in place, that the rubber sheet should 

 not be stretched over the mouth of the pressure chamber, but should rather have 

 some slack. Two gas pipes pass from the pressure chamber through the bin wall; 

 one of them leads to a U-tube containing a mercury column, while the other serves 

 as air vent during the process of filling the chamber with the liquid used. Glycerin 

 was used at first, though later water was also experimented with. Since the two gas 

 pipes turned off upward from the pressure chamber and were filled with glycerin at 

 the beginning of the test, they served to put the rubber membrane under some 

 initial pressure from the inside. 



"By this means it was made sure that the rubber surface would be slightly convex 

 toward the inside of the bin. The intention was to avoid any possible concavity 

 of the membrane; for, if the rubber surface were concave, part of the load on it 

 would be carried by the membrane acting as a suspension structure, instead of the 



