92 EXPERIMENT STATION EECOED. 



The peculiarities of curves obtaiued by platting calories of beat evolved by 

 cement during tbe period of setting against the time of setting " seemed to in- 

 dicate that the time of set and tensile strength are due to the colloidal nature of 

 cement. This is seemingly supported by references to the well known charac- 

 teristics of colloids." 



Solubility of cement tile, W. II. Day (Ann. Rpt. Ontario Agr. Col. and 

 Expt: Farm, 38 {1912), pp. JfS-Jfo). — Tests of the solubility of cement tile led to 

 the conclusion that in ordinary soil water there is no danger of dissolving and 

 crumbling in good cement tile which are not weaker in mixture than 1 : 4, are 

 thoroughly mixed, are of wet mixture firmly packed, are dried slowly during 

 initial set and kept wet for a week, and then well seasoned. 



Gas engines and producers, L. S. Makks and S. S. Wyeb ( Chicago, 1913, pp. 

 tS] -1-62+5, pis. 3, figs. 36). — This is a treatise on the modern development of 

 the internal-combustion motor, and of efficient methods of fuel economy and 

 power production. The work " is designed to present theoretical and practical 

 information in such form as to appeal both to the engineer and to the untrained 

 person who is merely interested in the subject." 



The subject matter under the division of gas and oil engines is as follows : 

 The external-combustion motor, the internal-combustion motor, the modern gas 

 engine, thermodynamics of the Otto cycle, ignition, governing, starting, water 

 jackets, the explosive mixture, the exhaust, modification of the Otto cycle, 

 gas-engine fuels, large gas engines, liquid fuels, and kerosene and crude-oil 

 engines. Under the division of gas producers are the topics of ga.seous fuels, 

 history and manufacture of producer gas, gasification losses, rules, representa- 

 tive types, gas cleaning, uses of producer gas, producer-gas power plants, and 

 gas poisoning. 



A new kerosene carbureter, G. M. Holley (Gas Engine, 16 {191.'f), No. 1, pp. 

 32-34, figs- 3). — A carbureter is described and diagrammatically illustrated 

 which is so arranged that in starting the engine the mixture consists of both 

 gasoline and kerosene. The gasoline supply is constant and the kerosene 

 supply can be slowly increased, until the engine is heated and running smoothly 

 on a high koresene mixture, at which point the gasoline may be cut off. This 

 device is said to accomplish prompt and smokeless starting. 



A unique kerosene carbureter, J. A. LrcAS (Power. 39 (1914), A'o. 1, pp. 14, 

 15, fig. 1). — This article describes and illustrates a kerosene carbureter, so de- 

 signed that the kerosene mixture when A-ery rich is partially ignited and thereby 

 heated before entering the combustion chamber. From the heating chamber the 

 mixture passes to the mixing chamber, where it is properly proportioned, and 

 then into the combustion chamber. This device is said to allow a motor to 

 start when cold, on kerosene, " apparently as easily as on gasoline," and also 

 to prevent excessive carbonization. 



Specifi-cations for motor power spraying machines (Fruit-Groioer and 

 Farmer, 25 (1914), No. 2, pp. IS, 19). — Specifications for motor spraying ma- 

 chines of several different makes are given m a table. 



How to harvest ice rapidly, H. B. Wood (Sci. Amer. 8up., 77 (1914), No. 

 1984, pp. 18, 19). — The author calls attention to the prime importance of speed 

 in the harvestmg of ice and describes methods of saving time and preventing 

 delays. 



Destroying stumps with acids, H. C. Coggins (Agr. Gaz. N. 8. Wales, 24 

 (1913), No. 11, pp. 967, 968). — ^Tests with sulphuric and nitric acids in varying 

 proportions for stump destroying proved unsatisfactory with both dry and 

 green stumps. It is concluded that sound stumps can not be destroyed with 

 either sulphuric or nitric acid, or both. The method is also wasteful of time 

 and the handling of acids dangerous. 



