EUEAL ENGINEERING. 589 



thickness of plate and working pressures. A sliglit modification of tlie Alberta 

 formula would make a practical and safe rule for uniform adoption. The 

 requirements regarding crown sheets for traction and portable boilers as given 

 by the Alberta and Saskatchewan rules are commended, with slight modifica- 

 tions in the angularity allowed for the stay bolts to deviate from the radial 

 lines." 



It is considered practicable and desirable for boiler laws and rules to be 

 uniform for all the States and Canadian Provinces. 



The relation of drawbar pull to the weight of a, tractor, C. M. Eason 

 {Threshermen' s Rev., 2Jt {1915), No. 8, pp. 8, 37, fig. 1). — A brief analysis of 

 the relation of drawbar pull to the weight of the tractor is given, and data 

 from different experiments are presented which indicate that the general 

 tendency in tractor development is toward obtaining more drawbar pull with 

 less weight of tractor. 



Testing the drawbar horsepower of tractors, C. M. Eason {Threshermen' s 

 Rev., 24- {1915), No. 9, pp. 14, 15, figs. 2). — A recording dynamometer for trac- 

 tion-engine testing is described and illustrated. This consists essentially of a 

 hydrostatic pressure unit which is hitched between the tractor and the load 

 being pulled, and a recording pressure gage connected to the hydrostatic unit 

 by means of a flexible tube. The dial of the recording gage is driven by a 

 gear reduction connected by means of a speedometer shaft to a trailer wheel 

 Avhich runs on the ground. To obtain the elapsed time a clock is provided 

 having a recording arm which checks the time intervals on the margin of the 

 pressure gage chart. 



Practical application of industrial and agricultural machinery for peat 

 bogs, L. A. Krupp {Jour. Amer. Peat Soc, 8 {1915), No. 1-2, pp. 1-11, figs. Jf). — 

 This article discusses the essentials of machinery for the manufacture of peat 

 fuel, fertilizer filler, peat humus, etc., and agricultural machinery, including 

 drainage and ditching machines, tractors, and the like designed for the prep- 

 aration of humus and peat soils for cropping. 



Capacity test of peat machine, G. Keppeler and C. Birk {Mitt. Ver. Ford. 

 MoorknUur Dcut. Reiche, 33 {1915), No. 10, pp. 251-258, figs. 5).— This article 

 describes a recently developed machine for the obtaining of peat on a large 

 scale from peat swamps and reports capacity tests. The results show that 399 

 tons of raw peat were obtained in 10 working hours. 



Tests of new dairy machinery, B. Martin y {Arh. Deut. Landw. Oesell., No. 

 277 {1915), pp. 56, figs. 31). — This is a classified report of preliminary tests of 

 a number of recent developments in dairy equipment. 



Description of the milking machines tried at the Alnai^p Institute (Official 

 Swedish Experiment Station for Agricultural Machines and Implements), 

 F. L. RosENGREN {Intemat. Inst. Agr. [Rome], Mo. Bui. Agr. Intel, and Plant 

 Diseases, 6 {1915), No. 2, pp. 285-290, pis. 2).— Tests of five suction and five 

 pressure milking machines are reported. 



The results showed that the cows submitted to the pressure machines less 

 easily than to the suction machines. The former also worked more slowly. 

 The quantity of milk obtained per minute was, in general, smaller than that 

 obtained by hand milking. With quiet cows, easy to milk, the intensity of 

 machine milking, at least in the case of suction machines was, in general, 

 as good as by hand milking, and often superior. The quantity of milk ob- 

 tained per minute depended not only upon the manner in which the machine 

 worked and the quietness of the cow, but also on the stripping and the care 

 of the milker. The gi-eater the yield of a cow the greater was the quantity 

 of milk obtained per minute. Complete milking out by machine to the last 

 drops of milk caused the quantity of milk per minute to fall. 



