M. Plateau has studied the power of traction in some insects, the power of pushing in the digging insects, and the lifting power of others during flight. He has thus been able to make some most interesting comparisons, of some of which we will relate the results.
The average weight of man being 142 lbs., and his power of traction, according to Régnier, being 124 lbs., the proportion of the weight he can draw to the weight of his body is only as 87 to 100. With the horse the proportion is not more than 67 to 100, a horse 1,350 lbs. in weight only drawing about 900 lbs. The horse, therefore, can draw little more than half his own weight, and a man cannot draw the weight of his own body.
This is a very poor result, if compared with the strength of the cockchafer. This insect, in fact, possesses a power of traction equal to more than fourteen times its own weight. If you amuse yourself with the children's game of making a cockchafer draw small cargoes of stones, you will be surprised at the great weight which this insignificant looking animal is able to manage.
To test the power of traction in insects, M. Plateau attached them to a weight by means of a thread fastened to one of their feet. The _Coleoptera_ (Beetles) are the best adapted for these experiments.
The following are some of the results obtained by the Belgian physician:--_Carabus auratus_ can draw seven times the weight of its body; _Nebria brevicollis_, twenty-five times; _Necrophorus vespillo_, fifteen times; _Trichius fasciatus_, forty-one times; and _Oryctes nasicornis_, four times only. The bee can draw twenty times the weight of its body; _Donacia nymphæ_[7] forty-two times its own weight.
From this it follows that if the horse possessed the same strength as this last insect, or if the insect were the size of a horse, they would either of them be able to draw 155,250 lbs. M. Plateau has ascertained the pushing power in insects, by introducing them into a pasteboard tube, the interior of which was made rough, and in which was fixed a glass plate, which allowed the light to penetrate into the prison. The animal, if excited, struggled with all its strength against the transparent plate, which, on being pushed forward, turned a lever adapted to a miniature dynamometer, which indicated the amount of effort exercised.