16 Dr. Hare's reply to Professor Olmsted. 



particles, by the heated boiler, cannot move the piston. In 

 order to shew that I have committed a mistake " here" it 

 must be proved that it is conceivable that, the particles of 

 steam should by a force arising from their motion, impart to 

 the piston the wonted power, or that particles of air, should, 

 in like manner, " support a column of mercury infinitely 

 heavier.'''' 



It evidently would be absurd to suppose that the piston of 

 a steam engine could be propelled, by the direct influence of 

 caloric, without the intermediate effect of the elasticity of 

 vapor. 



The author combats strange opinions, peculiar to his own 

 imagination, as if I were answerable for them. 



" It is difficult, says Professor Olmsted, to see why heat 

 should impart such a wonderful power to steam ; nor doe8 

 our supposing it to be a material fluid diminish this difficul- 

 ty." He might with equal propriety add, it is difficult to un- 

 derstand how light can impart to the objects around us, the 

 wonderful property of conveying their images to the senso- 

 rium ; nor does the idea of a material fluid, passing from 

 them to the retina of the eye, diminish the difficulty. 



It is difficult to understand why lead should be heavy ; nor 

 does the idea, that the earth attracts it, diminish the dif- 

 ficulty. 



My mind is much less embarrassed by supposing a cause, 

 where I observe an effect. Wonderful as it is, that the earth 

 should by solar attraction be kept in its orbit, to me it is much 

 less wonderful than if there were no Sun to attract it ; wonder- 

 ful as it is that all the phenomena of vision should be due to 

 the reflection, refraction, or polarization of a subtile matter 

 emanated from every luminous point in the creation, the phe- 

 nomena in question appear to me far less perplexing, than 

 when I endeavor to dispense with the agency of a material 

 cause. The opposite properties of the tenacity of ice, and 

 the explosiveness of steam, however surprizing, are less so 

 when considered as belonging to different kinds of matter, 

 than when I suppose them alternately assumed by the same 

 particles, so as to cohere at one time, and at another fly apart, 

 with violence, without any cause for the change. 



It seems to me, that without the special interference of the 

 Creator * the properties of any species of matter must always 

 remain the same. Should any property appear to cease, or 

 to be varied, there must be an accession, or an avolation of 



