PROFESSOR OLMSTED'S OBJECTIONS. 433 



I am willing to suppose the Professor misunderstood me 

 when he staled that I drew the deduction, that because cloud 

 was formed in the nephelescope when the air expanded, 

 therefore all clouds in nature were so formed. This, I never 

 stated, either in writing or in my lectures, as a deduction 

 from this experiment alone. The deduction which I drew 

 was that, if it could be demonstrated that currents of air rose 

 up from the surface of the earth to a certain height, depending 

 on the dew point, and temperature of the air at the time, 

 cloud would be formed, and that too on the very principle 

 on which they were formed in the nephelescope, by the cold 

 of expansion from diminished pressure ; whether all clouds 

 are so formed or not, depends on other proof. It did not ap- 

 pear to me very clear, whether the Professor acknowledged 

 there would be any cold produced in the air from diminished 

 pressure, even if a current of air should ascend, unless it 

 had been previously condensed as in the nephelescope and 

 at the Chemnitz fountain; for he said a man would feel 

 cold if taken up to a great height without expanding from 

 diminished pressure. This argument does not seem to me 

 to require an answer. 



Professor Olmsted did not do me justice when he said 

 that I had stated in my lecture as an argument in favor of 

 the truth of my theory, that scientific men were generally 

 against me. I did not mean to be so understood. 



The Professor had stated in a previous lecture, that " as 

 I had failed to convince scientific men of the truth of my 

 theory, I had appealed to the people," who, he insinuated, 

 were incompetent to decide the question. In my lecture, I 

 thought it but right to acknowledge that a large portion of 

 the scientific world were against me, and mentioned Sir 

 John Herschel as among the first men of the age; but I 

 denied, that that settled the question; and I immediately 

 attempted to shew, by reasoning so plain that the people 

 could understand it, that the argument which Sir John 

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