Vol. XII. No. 296. 



THE AGRICULTURAL NEWS. 



279 



AGRICULTURAL ENGINEERING 



THE EFFICIENCY OF MANUAL LABOUR 

 IN DIFFERENT OPERATIONS. 



Tbe researches of Max Kingelinann, which are ilt-scribed 

 in the Annales de U Inst it id' Xntuinnl Ayroiwiniijue, 

 (•Jl- Serie, Torae XII) under the title of Researches sur les 

 Moteurs Animi'S Travail de 1' Homme, may be drawn 

 upon with advantage for ioforniation on the subject of 

 the effectual utilization of human labour in different 

 mechanical operations. 



The investigator referred to, obtained the assistance of 

 a large number of students for tbe purpose of conducting 

 experiments on them to determine the maximum effort which 

 men are able to exert under the conditions to be described 

 later. 



The first series of experiments may be conveniently 

 referred to from the point of view of the general conclusions 

 that may be drawn from them. The trials consisted in the 

 exertion of a pulling force on a dynamometer. It was found 

 that the nature of the ground surface made a great difference, 

 and it is noted that in inclining the liody for the purpose of 

 pulling, no simple friction is produced on the soil, but rather 



exhibition of strength wis, for (5), 1220.'? ft), and for (<)), 

 i;5.5-.54 !b. A third trial (7) in this same series, was pulling 

 in a similar manner to that adopted in (6), except that the 

 rope was passed around the small of the back. This proved 

 most efficient, 152-33 DE>. being the result. 



(2) 



Fig. 12. 



what may be termed an anchorage {an^ratje) resulting from 

 the inclination of the sole. liut the essential result 

 obtained was this: that in employing men (and also 

 animals) the best utilization is realized only when the 

 motor works alone; since when one joins together two or 

 several motors, useful work diminishes by reason of the lack 

 of simultaneousness in their efforts. 



Turning now to the tests in regard to different oper- 

 ations, the first one consisted in pulling a rope laterally with 

 two hands, against pulling a rope passed over the shoulders. 

 The maximum effort exercised was for (1), 138 33 &., and 

 for (2), 90-5.5 lb. The next test was (3) pulling on a cross- 

 bar attached to the end of a rope, against (4) pulling it 

 behind the back. The result was for (3), 187-70 ft) , and for 



(4) ■ (5-. 



Yio. 13. 



(4), I26-d5 ft). After this, the .'•tudcnts had to try pulling on 

 a rope passed around the shoulder (5j. against pulling in the 

 same way but facing the resistance (6;. The result of this 



(7) ^ (8) 



Fk;. 14. 

 The subjects under experiment were then attached' 

 individually to a two- wheeled cart. In this series, t he- 

 contest was between (f<) pushing against a weighted cross- 

 bar at the end of the single shaft pole, and (9) doing the- 

 same, but aided by passing a rope attached to the shaft, 

 around the shoulder; and, thirdly, (10) pushing instead of 

 pulling the cart as in (8). The results were as follows; 



Fi.;. 15. 

 (8), 17G lb, (about); (9), 187-84 lb.; (10), 123 02 ft. An altera- 

 tion in the weight of the bar did not make much difference, 

 but when more than one motor was employed there was- 

 a notable loss of effective power. For instance, two men 

 working together as in (8) exerted a combined effort much 

 less than the total of their exertions when operating singly. 

 This is clearly indicated in the following table:— 



Total, Per man. Per man 



working siagly,. 

 ft, ft. ft- 



Two men working as in (8) 314 95 157 48 176-88 



„ „ (;)) 338-98 169-49 187-34 



ttW) 

 . Fi.^, 1.6. 

 This account will be continued in the next issue of the 

 Agrtriiltiirnl Xcirx, when consideration will be given to the 

 practical application of these and, similar results in tropical" 

 agriculture. , ■ 



