190 EXPERIMENT STATION EECOED. 



it solidifies in cold air, tlius minimizing the possibility of leakage; and it lias 

 a definite composition. 



In French tests of this fuel a 4-cylinder motor with a 135-mm. bore and a 

 145-mm. stroke developed 35 b. h. p. at 888 r. p. m. at a cost per brake horse- 

 power hour of about ^ ct, and a 2-cylinder motor with an 88-mm. bore and 

 140-mm. stroke developed 8 h. p. at 1,100 r. p. m. at a cost per brake horsepower 

 hour of about ^ ct. 



The naphthalin motor, O. H. Haenssgen (Oas Engine, 15 {1913), ISlo. 10, 

 pp. 537-542, figs. 6). — The mechanical details and operation of several makes of 

 both 2- and 4-cycle motors operating on naphthalin fuel are described. All of 

 these require a light liquid fuel for starting and stopi3ing and for generating 

 heat, either in the exhaust or in the cooling water, sufficient to melt the 

 naphthalin. 



Connecting electric motors for direct drive, C. B. Mills (Brick and Clay 

 Rec, 43 (1913), No. 5, pp. 468-470, figs. 2).— This article takes up the purely 

 mechanical considerations in the application of electric motors to machinery and 

 deals with the advantages and disadvantages of several styles of connection 

 between motor and machine, including belt, rope, toothed chain, gear-and-pinion 

 connections, and cushion and flange couplings for direct connections. 



The transmitting powers of belts and ropes at various speeds are graphically 

 represented and designs of connections are mathematically analyzed. It is 

 stated that since the armature of the average type and size of motor is com- 

 posed of a great number of parts of little mechanical strength it is important 

 to choose a method of connection which will tend to absorb or minimize shock 

 and vibration. 



Installation and care of storag-e batteries, H. M. Nichols (Sci. Amer. Sup., 

 76 (1913), No. 1965, pp. 130, 131).— This article considers the layout and instal- 

 lation of storage batteries and takes up in detail their operation and mainte- 

 nance, including the location and correction of the most frequent troubles. 

 These are enumerated as short-circuiting, sulphating, flaking, disintegration, 

 and warping of the plates. It is stated that each cell in a battery should be 

 carefully inspected and tested, when fully charged, once a week, and that a 

 record should be kept of weekly inspections of each cell for comparative 

 purposes. 



The Winnipeg tractor trials, L. W. Ellis (Sci. Amer., 119 (1913), No. 10, 

 pp. 201-204). — These trials, the sixth of their kind, brought out the fact that 

 both large and small farmers are now more keenly interested in the medium to 

 small general-purpose tractor. 



The tests consisted of (1) a 2-hour economy brake test; (2) a i-hour maxi- 

 mum brake test; (3) a 8 to 5-hour economy, efficiency, and capacity plowing 

 test; and (4) a careful comparison of design and construction. Out of 500 

 points the first was allotted 150, the second 50, the third 200, and the fourth 

 100. The highest net score attained was 4.37.3 points. The brake showings 

 were quite uniformly good, and little distinction was made between the tractors 

 on design and construction. A new feature was the use of a vibration de- 

 tector. The most severe criticisms on design and construction were on lubri- 

 cating systems and insufficient protection of working parts from mud and dust. 



The plowing tests were held on ground which had been plowed before and 

 which had a 2 ft. growth of weeds. The average cost of plowing per acre for 

 steam engines was 46.3 cts., for kerosene 50.9 cts,, and for gasoline 62.1 cts. 

 The 5- and 6-plow tractors plowed about 1* acres per hour, the 4-plow rigs 

 about 1 acre, 8-plow rigs behind large gas tractors 2i acres, and 10-plow rigs 

 2f to 3 acres. Plow for plow the steam engines showed more capacity, largely 

 due to higher geared speed of travel. 



