488 EXPERIMENT STATION RECORD. 



a chemical change and is advanced as an explanation of concrete tile drain 

 failures within a few hours after laying. 



Control of initial setting time of Portland cement, E. E. Ware {Jour. Indus, 

 and Engin. Chem., 5 (1D13), No. 5, pp. 369-311, fig. i).— The results of a large 

 number of experiments to test the retarding effects of different added mate- 

 rials, such as gypsum, hydrated lime, calcium chlorid, and acids on the initial 

 setting time of rapidly setting Portland cement are reported as apparently un- 

 successful, and these, in connection with the opinions of various authorities as 

 to the cause of the quick setting of cements, indicate that it is not due to free 

 lime. Additional experiments along the line of hydration were tried with sat- 

 isfactory results, the cement ground from clinl^er, which showed an initial set 

 of from 3 to 5 minutes'under the ordinary procedure, being slowed to from 2^ 

 to 3 hours when hydrated to the extent of less than 2 per cent. 



No definite conclusions are made, due to the continuation of the experiments 

 to determine the action of alumina and gypsum during initial setting. 



Power transmitting capacities of pulleys, J. S. Leese {Power, 37 {1913), 

 No. 18, pp. 628, 629, fig. 1). — The results of a number of tests made to deter- 

 mine the relative transmitting power of wood, paper, and cast-iron pulleys with 

 leather belts show the maximum transmitting capacity, of paper pulleys to be 

 29.8 per cent better than cast-iron, and 107.7 per cent ffetter than wooden 

 pulleys. 



Measurements made during these tests to compare the temperatures of the 

 surfaces of pulleys show the wood pulleys to be the hottest, paper next, and 

 cast-iron the coolest with a constant power of 8 h. p. per square inch cross 

 section of the belt, and the paper the hottest, with the wood a close second, 

 under a constant belt speed of 3,500 ft. per minute. 



The prony brake and its use, H. M. Phillips {Power, 37 {1913), No. 19, 

 pp. 68S-690, fig. 1). — This article gives an elementary explanation of the prony 

 brake, describes common errors in its application, and gives complete directions 

 for its correct use. 



The effect of added fatty and other oils upon the carbonization of min- 

 eral lubricating oils, C. E. Waters {U. 8. Dept. Com. and Labor, Bur. Stand- 

 ards Technol. Paper Jf, 1911, pp. 14)- — The results of tests are given for de- 

 termining the amount of carbonization of a straight mineral engine oil flashing 

 at 140° and of the same oil with known amounts of other constituents, such as 

 lard or rosin oil, tallow, etc. 



The results indicate that the admixture of other oils with the mineral oil 

 caused a greater or less diminution in the amount of insoluble and total 

 residue. The addition of asphalt increased the percentage of insoluble residue. 

 Sulphur and paraffin caused no marked difference, while linseed oil enormously 

 increased the amount of total residue. 



It is concluded that the addition of various oils and substances to a straight 

 mineral oil affects the amount of carbonization and that lubricants containing 

 soap in quantity, rosin, and asphalt, or which have been exposed to the action 

 of sunlight and air, are to be avoided. The addition of tallow and lard oil is 

 not recommended, although low results were obtained with such mixtures, 

 since the presence of the fatty acids resulting from the decomposition of the 

 oils may greatly increase the corrosion of the engine cylinder and in actual 

 practice cause as much carbonization as the direct addition of ferric oxid. 



Machinery adopted for use on moor plantations, H. Akerberg {Svenska 

 MosskuUurfor. Tidskr., 27 {1913), No. 2, pp. 116-131, figs. 35).— This article 

 describes machinery and tools used in the farm work at the Flahult Moor Cul- 

 ture Station. 



