between a Machine and Us Model 153 



they consume, than moderately-sized ones are ; and, in many 

 instances, it would have been better to have employed two or 

 three middle-sized engines than a single one possessed of two or 

 three times the nominal power. 



Every instrument, whether it be used for the generation or 

 for the transference of power, has a best size and a best form. 

 The contemplation of the whole animal and vegetable kingdoms 

 teaches this truth. Each species of animal attains to a deter- 

 minate size, beyond which it seldom proceeds, and short of 

 which it seldom stops, unless man has interfered with the regu- 

 lar course of nature, and deranged, as his contrivances too often 

 do, that determinate succession of events which is conspicuous 

 in the history of each tribe of what we are pleased to call the 

 lower animals. Each animal and each vegetable, in its progress 

 from infancy to maturity, assumes, at each stage of that pro- 

 gress, such a form as best assorts with the consolidation of its 

 parts, and with the mode of its living. The wisdom and the 

 beneficence of this arrangement, and the skilfulness with which 

 it is made, become the more apparent when we carry our con- 

 templations beyond the globe which we inhabit to those other 

 worlds which circulate round the same sun. Were man, in his 

 present state, and with his present powers, planted on the sur- 

 face of Jupiter, he would be crushed beneath his own weight : 

 and if, on the surface of that planet, there do exist beings of the 

 same structure and of the same material as man, one of us would 

 be a Man-mountain among them. If, on the other hand, we 

 were transported to the surface of the Moon, or of one of the 

 Asteroids, our strength would fit us for progressing rather in 

 the manner of the grasshopper than of the man : bipeds, living 

 and moving as we do, would there realize the counter- vision of 

 Gulliver. 



The sizes, then, of the objects which, on the surface of this 

 earth, surround us, are not fixed by chance, but determined by 

 the immutable laws of nature ; and, in every case, Nature has 

 pushed her exertions to the utmost. There is a limit, both 

 ways, to the size of quadrupeds ; there is a limit, both ways, to 

 the size of birds ; and, although myriads of insects may be as 

 yet unknown, I hesitate not to afKrm that, among these also, 

 we have the double limit. These are not mere speculative 



