AGRICULTURAL ENGINEERING. 935 



a paste and well tamped, its volume was 1.34S en. yd., which shrunk hut slightly in 

 4 days. 



••When mixture No. 4 wa.s luixt-d dry and tamped, its volume Avas 1.2(5 eu. yd. 

 \Vhen mixed dry and poured from a height of 0..S.5 ft. into water, and mixed hut not 

 tamped, its volume was 1.201 cu. yd. When mixed dry aud moistened with 0.80 cu. 

 yd. water into a still" ])aste and well tami)ed. its volume was 1.212 en. yd." 



Devices for obtaining a constant flovr in laterals with variable 

 heads in the main canals or reservoirs, A. M. Kyon {Montana Sta. 

 Jiiil. 11, pp. W-:)S,ji(js 1). — The iinpoitauce of better iiieaus of ooutrol- 

 lius" and measuring irrigation water is pointed out and tliree devices 

 for this purpose are described — the Decker siplion niocUile and auto- 

 matic i)rorater. Foot's spill box, and an automatic gate designed by 

 the author. The latter is a gate operated aud controlled by afloat and 

 a weight, so arranged that a rise in the water of the canal rai.sos the 

 float and closes the gate, thus eiiualizing the flow. The u.se of this 

 device involves no loss of head in the main canal, but a los.s in the 

 lateral, amounting in the test here reported to (>.<i to ().!> ft. in addition 

 to the head used by the measuring box. 



Traction tests, S. T. Xeely ( U. S. l)ept. Agr., Office of Road Inquiry 

 Bui. :J0, pp. 9-:J:J, jyls. ^, Jigs. 7). — An account is given of traction tests 

 on the roads of the IJuited States road exhibit at the Cotton States 

 ami International Exi>osition at Atlanta in 181>5, and on roads in the 

 vicinitj' of Washington. Tests were made on macadam, sand, and 

 dirt roads, level and with different grades, and on asphalt pavement, 

 with a tractoraeter, in which the amount of force which the team exerted 

 was weighed by a spring in compression, and was indicated on an arc 

 by means of a pointer, and by a "tractograph," an apparatus similar 

 to that used on steam engines to obtain indicator diagrams. The 

 tractograph diflered from the tractometer in that ''a long arm, holding 

 a pencil at its end, was attached to the end of the piston which pre- 

 viously moved the pointer. The pencil point rested on a revolving 

 cylinder which Avas placed in front of the spring and piston and 

 extended longitudinally along the pole. This cylinder was made to 

 turn by means of gear driven directly by one of the front wheels of 

 the wagon. A further change was made by substituting a single long 

 spring in place of the two short springs previously used."' 



The results with the tractometer are summarized as follows: 



"On the smoothest possihle macadam road surface the force of tracti(m was not 

 constant, hut changed eontinnously within a r.iuge of 50 lbs. 



"On th<! onlinary dirt road the force varied from to 700 lbs. (in a gross load of 

 3,000 lbs.), becoming iu etfeet a rapid succession of violent jerks. 



"Some method should be adopted of making a more elastic connection between 

 the wagon and the team, thus transmitting the shocks at the wheel rims as a gradual 

 change of force to the teana. 



"On heavy grades, in the case of the smooth load, the force was more nearly 

 con.stant. 



"The force necessary to start a load on the smooth road was 4 times as great as 

 the force required to draw the load at a uniformly slow pace when started aud was 

 one-tenth the gro.ss load. 



