888 ■ EXPERIMENT STATION RECORD. 



general need for drainage in arid regions witli reference to seepage and alkali 

 problems, and is intended to cover "all engineering phases of farm drainage 

 from the general observations concerning specific needs of drainage to the reali- 

 zations of successful reclamation." 



The road problem, J. H. A. Macdonald (Rpt. Brit. Assoc. Adv. Sci., 1912, 

 pp. 373-383). — The author discusses the past, present, and future of road con- 

 struction, particularly pointing out the marked disadvantages resulting from 

 road rolling, such as the formation of transverse ridges and furrows, the for- 

 mation of potholes where road metal is mixed with mud and rolled, and the 

 tendency to use too large stones. He draws attention to the enormous in- 

 crease in motor traffic and concludes that present and future construction, 

 particularly of the road crust, must in consequence be adapted to the traffic. 



Mechanical engineering aspects of road construction, R. E. Crompton 

 {Surveyor, ^5 (1914), ^^o. 1146, pp. 4-10, figs. 6). — The opinion is expressed that 

 the development of road locomotion must be jointly studied by vehicle de- 

 signers and road engineers. A brief review of the development of self-propelled 

 vehicles and a description of the waving of road crusts and the conditions 

 which cause and accentuate them are followed by the author's views as to the 

 methods of road crust construction to prevent or minimize such action. It is 

 pointed out that there is a great tendency for modern motor vehicles of the 

 heavier classes to have nearly the same percussive and rebounding effects, and 

 that the frequent passage of such traffic along a road tends to produce a regular 

 wave formation of equal wave lengths. Initial waving is said to be produced 

 in the process of rolling, and the use of a special three-axle roller is advocated. 



In conclusion it is shown in tabular form the extent to which the present 

 running costs of vehicles may be reduced by a well considered reconstruction of 

 road surfaces. 



Construction of bitumen bound broken stone roads, J. W. Smith (Good 

 Roads, n. ser., 6 ^{1913), No. 10, pp. 99-110). — In a paper before the Third 

 International Road Congress, London, it is concluded that by the use of tarry, 

 bituminous, or asphaltic binders a number of different forms of road crust may 

 be obtained which may be employed with advantage according to the various 

 conditions of the road as regards traffic, locality, and climate. For this purpose 

 it is suggested that a uniform system of tests, measurements, and records be 

 drawn up, including physical and local conditions, materials employed, method 

 of construction, traffic census, climatic conditions, periodical measurement of 

 wear, and actual cost of the road crust as regards construction and mainte- 

 nance. Other related subjects are discussed in detail. 



Agricultural surveying laboratory manual, D. Scoates (Agricultural Col- 

 lege, Hiss., 1913, pp. 33). — This manual, intended for the student of agricultural 

 surveying, deals with the principal basic problems of the subject, giving assign- 

 ments with instructions as to procedure, noting the necessary equipment, and 

 including a set of sample notes for each problem. 



Variations in results of sieving with, standard cement sieves, R. J. Wig 

 and J. C. Pearson {U. S. Dept. Com., Bur. Standards Technol. Paper 29 (1913), 

 pp. 16, fi,g. 1). — A number of tests to determine what order of discrepancy may 

 be expected in fineness determinations of cement by the standard routine 

 method of sieving included investigations on differences in the standard sieves, 

 the so-called "personal equation" of the observer, lack of uniformity in 

 samples, and residual errors. 



It is concluded that both sieving tests and the inteiiJretation of measurements 

 on sieves are subject to considerable discrepancies, that errors due to "personal 

 equation" are appreciable in hand sieving, and that the rating of a sieve by 



