Voz. XII. No. 297 



THE AGKICULTQRAL NEWS. 



295 



AGRICULTURAL ENGINEERING. 



THE EFFICIENOY OF MANUAL LABOUR 

 IN DIFFERENT OPERATIONS. 



It was endeavoured in the last issue of the A'lricidlnral 

 -Vfifs to present as briefly as pnssil)le some of the results 

 that Professor Max liingelinann obtained in regard to the 

 •.naxiinuin effort exerted in ditt'erent manual operations. In 

 continuation of the subject, further series of trials will be 

 described and a few remarks made in regard to its agricul- 

 tural importance. 



The third series nf experiments consisted in determining 

 the maximum effort exerted in pulling a two-wheeled cart. 



/\ 



I > 



(11) 



Fig. 19. 

 The efi'ort exerted in pulling on the .shafts with both hands 

 (11) wa.'; 14. 5' 33 D).; pulling with the aid of a rope 

 1.52-59 ft.; pushing the .shafts S,S'OI Bb. The maximum 

 efforts represented by these figures are much more 

 feeble than in the other series described in the last 

 article, where the cross-bar was employed. There is always 

 ,a great wa.ste of energy when pulling by means of shafts 

 owing to the torsion of the arms at an angle of 90°. 



The subjects were next involved in an experiment with 

 an ordinary wheel-barrow. The weights represented by j». in the 

 :^irst series (12) and the results obtained were: 13'2 lb and 

 103-88 lb. (maximum effort); 242 fc. and 111-94 ft.; 3-5-2 ft. 





_j/--i'./\ 



(12) 



Fig. 20. 

 and 107-58 ft. respectively. In the second series (pulling 

 instead of pushing) the results were as follows: 132 ft. and 

 109-82 ft; 24-2 ft. and 11642 ft ; 3.5-2 8). and 12038 ft., 

 respectively. It will be noted that higher results were 

 obtained by pulling than by pushing, but it muse be remem- 

 bered that, in practice, the difficulty "f steering and main- 

 taining an equilibrium when pulling, are disadvantages which 

 lend to offset the greater power that can be exerted. 



The final series consisted in pushing a trolley. The 

 results obtained were as follows: (13) pushing 1 ra. -05 above 

 the track level 136-88 ft.; (14) pu.shing m. -34 above, 

 11004 ft.; (15) pushing with the foot m. 34 above, 

 84-22 ft. It will be noticed that the bent attitude causes 

 "the loss of much effective effort. 



PRACXICAL -\SPECTS OF THE SUBJ£< -f. 



When we come to consider these results, and those 

 described in the last article in connexion with manual labour 

 in the West Indies and Tropics generally, the first feature of 



interest which strikes one is the principle of combined action. 

 This depends on the circumstance that the sum of th» 

 maximum efforts of a number of men engaged in a certaia 

 piece of work is much less than the sum of the efforts whea 

 each is working independently. The familiar habit amongst 

 the labouring classes to sing whilst exerting combined effort 

 is therefore seen to have a scientific basis and is to bo 

 encouraged. Another point of much significance brought 

 out l)y the foregoing results, is the usefulness of a rope 



attachment. In pulling a cart a rope passed round the 

 shoulder enables a man to exert a maximum effort 12 B>. 

 greater than would be the case without one. In the VVast 

 Indies, the tractive powers of men are chiefly used in con- 

 nexion with the shipment of cargo. The trolley system is 

 still in vogue on many of the island piers, whilst the hand- 



(15) 

 Fig. 23. 



cart is used for conveying sugar and other produce from tho 

 warehouses. No harm can accrue by bearing in mind, ia 

 regard to these operations, the results of the tests indicated 

 above. 



