188 EXPEKIMENT STATION EECOKD. 



pp. 494, 495, figs. 4). — The mathematical analyses given of tne design of sheet 

 steel and wooden stave pressure pipes include the derivation of formulas for 

 thickness of steel pipe, size and spacing of bands, and size of staves for wooden 

 stave pipe. Wooden stave pipe are claimed to be cheaper than steel pipe, not 

 subject to corrosion, to have a greater carrying capacity than a riveted steel 

 pipe of the same diameter, if kept saturated to be of probably greater dura- 

 bility, and to be unaffected by heat or cold. Its disadvantages are that it must 

 be kept saturated continually and is liable to destruction by fire. 



Methods of constructing reinforced concrete pressure pipe are described. 



The economics of pipe line diameters {Engin. and Contract., 40 {1913), 

 No. 9, pp. 237-240, figs. 8). — In a paper taken from the proceedings of the 

 Pacific Northw^est Society of Engineers C. W. Harris analyzes, mathematically 

 and graphically, methods for determining economical pipe line construction for 

 power development, water supply, and irrigation, considering first the smallest 

 pipe which will deliver a given amount of power ; second, the smallest allowable 

 diameter without exceeding allowable velocities; and third, economical diame- 

 ter considering the value of the water right. 



The following points are summarized as solutions to these considerations : 



When the water consumed has no value it is allowable to use the smallest 

 possible pipe line for power which, with a friction loss of one-third of the total 

 head, will deliver a quantity of water sufficient to produce the required power 

 with the other two-thirds of the total head. 



If a pipe line is subjected to a varying head throughout its length, but the 

 cost for any particular diameter remains constant for those various heads, the 

 diameter should also remain constant throughout; but if the cost of the pipe 

 is dilferent for the different heads the diameter should be smaller for the larger 

 head. The correct diameter under any particular head is that which will make 

 n/5 of the cost of the pipe for a given length equal to the capitalized value 

 of the power consumed by friction in that same length, n being 2 for steel pipe 

 and 1.5 for wooden stave pipe, and for any pipe taking the index of d in the ex- 

 pression. Cost = M"-, in which k is a constant depending on the cost of steel 

 per pound, interest, depreciation, etc. With this diameter determined under 

 one head the diameter of the same pipe under any other head should vary 

 inversely as the seventh root of the head if the pipe is a high-pressure steel 

 pipe, or as the ninth root of the head if the pipe is wood stave. If the quantity 

 to be delivered is fixed, and the available friction loss is also fixed, as is the 

 case with a pipe line connecting two reservoirs of fixed elevations, the diameter 

 of the pipe line should vary throughout the length thereof according to the 

 laws expressed* above, the head to which the pipe is subjected being the static 

 head for which the pipe is designed. 



Light-iron irrig'ation flume (Engin. Rec, 68 (1913), No. 6, p. 153, figs. 3). — 

 This article notes the use of light semicircular ingot-iron smooth flumes 

 installed on a light wooden substructure on the Pala Indian Reservation in 

 California. The sections vary from 12.5 to 15 in. in radius. After comple- 

 tion carrying-capacity tests gave a value for the coefficient of roughness in 

 Kutter's formula of 0.010 for a 30 in. diameter flume. The total cost, including 

 substructure, was $2.61 per lineal foot. 



Heavy oil as fuel for internal combustion engines, I. C. Allen (U. 8. 

 Dept. Int., Bur. Mines Tech. Paper 37, pp. 36; Sci. Amer. Sup., 76 (1913), No. 

 1977, i)p. 326, 327; Indus. Engin. and Engin. Digest, 13 {1913), No. 9, pp. 392- 

 395). — ^A review of heavy fuel oils available for use in internal combustion 

 engines is followed by a discussion of heavy oil engines, including the Diesel 

 and semi-Diesel types and a summary of the requirements of heavy oil engines 



