RURAL ENGINEERING. 185 



the use of gasoline. This fuel is made from paraffin, its conversion being ac- 

 complished by a chemical process and without the use of heat. From numerous 

 recent tests, the claims are made that it is superior to gasoline in efficiency, 

 economy, and cleanliness, and can be used in any ordinary type of carburetor. 

 The cost of the finished product is estimated at about 25 per cent less than 

 gasoline. 



Notes of agricultural tractors, M. Ringelmann {Ann. Inst. Nat. Agron.. 

 2. ser., 11 {1912). No. 2, pp. 223-2J,l. figs. 7).— Several tractive effort curves and 

 tables of data are given from 16 dynamometer tests of 9 different motor plows. 

 For purposes of comparison the results are computed from a 100 meter length of 

 furrow plowed by each machine, and the variations in tractive effort are cal- 

 culated in percentages of the average tractive effort. 



The maximum tractive effort for the 9 machines varied from 110.55 to 154.70 

 per cent of the average tractive effort required, over lengths of plowing varying 

 from 2 to 27 per cent of the total length. It is concluded that the tractor should 

 be designed to exert a maximum tractive effort at the draw bar of 1.75 times 

 the average tractive effort required by the plow, thus providing for power losses 

 caused by friction, starting, and the sinking and slipping of the drive wheels. 



Standards in gas tractor construction, W. C. Brandon {Gas Engine, 15 

 (1913), No. 2, pp. 101-106). — This is a paper read before the American Society 

 of Agricultural Engineers in which the author points out the importance of 

 standardization in the design and construction of gas tractors. Among the 

 parts of the gas tractor which he considers to be fit subjects for standardization, 

 are horsepower rating, magneto dimensions, spark plugs, screw threads, bolt, 

 nut, and screw heads, wheel tire sections, carburetor fittings, plow hitches, and 

 draw bars. 



An experience in steam [plowing], N. Jackson {Canad. Threshcrman and 

 Farmer, 18 {1913), No. 3, pp. 46, 71, fl-gs. 2). — From comparative experiments 

 with the use of animal and mechanical power for plowing it is stated that by 

 the use of a 32 h. p. cross compound steam tractor, burning coal, an average of 

 16 acres of land per day was plowed, cultivated, and sown to flax in one opera- 

 tion at a total average cost of $1.87 per acre, while a neighboring piece of land 

 received the same treatment by animal power at a total average cost of $6.50 

 i)er acre. Using flax straw as fuel the same engine plowed 24 acres per day 

 at a total average cost of SS cts. per acre. 



Power plowing in the Philippines, Z. K. Miller {Philippine Agr. Rev. 

 [English Ed.], 6 {1913), No. 2, pp. 66-73, pis. Jf). — A number of experiments 

 witli traction and steam cable outfits, plowing in various soils, are reported. 



The results indicate the superiority of the disk plow over the gang plow in 

 hard ground covered with trash. It is shown that the cost of traction plowing 

 in the Philippines depends almost entirely on the class of soil, fuel, and season, 

 and varies from 70 cts. to $3.50 per acre. The cost of plowing with the cable 

 plow will vary from $2 to $3 per acre according to the condition and kind of 

 soil, but it is stated that the first cost of the steam cable outfit makes it prohibi- 

 tive on the average plantation. 



Motor plows and cultivating machinery, Luedecke (Fiihling's Landw. Ztg.. 

 61 {1912), No. 23, pp. 785-807, figs. 8).— This article deals with the economy of' 

 motor cultivation, gives reports of fair success from various experiments with 

 motor plows, and describes several types of tractors, tractor plows, and disk and 

 moldboard gang plows, giving considerable information and data in regard to 

 their operation, first cost, and cost of operation and maintenance. Various 

 Investigations show that on a large number of farms where mechanical power 

 is used it is cheaper to use some animal power. In consequence, it is sug- 

 gested that in all cases a careful and accurate study of conditions be made in 



