132 Mr. Meikle on the 



alike unfortunate for this theory whether the motion of sound 

 ultimately turn out, from experiment, to be uniform or retarded ; 

 for, independently of that, the result is anything but a fair 

 logical deduction from correct data. I have as yet confined 

 my remarks to Mr. Ivory's investigation in the Phil. Mag. for 

 July, 1825. His other solution grafted on it, and given in that 

 Journal for April 1827, is one way or other liable to all the 

 abovementioned objections. The difference between his two 

 solutions is owing to the innovations of his new law of con- 

 densation — an extraordinary production — the result of at least 

 seven years' researches on the subject *. So far, however, 

 from its being the lie plus ultra of science, as we should have 

 reasonably expected, and as its author has more than once 

 hinted, I doubt if, in point of absurdity, the like has been put 

 on record since the dark ages. A few cases, where it leads to 

 most erroneous results, are noticed in the Edin. Phil. Jour. 

 for April, 1827 ; and I shall now state the law briefly, with an 

 example or two of its unparalleled absurdity. 



Let r be the temperature on Fahrenheit's scale of an air- 

 thermometer, when a mass of air begins to undergo a change 

 of density ; and § the quotient obtained by dividing the density 

 at the end of the operation by that at the beginning. Then, 

 according to Mr. Ivory, the change of temperature due to such 

 change of density is 



i - A (448° + t) X ^^. 



8 p 



Among the many extravagant and contradictory conclusions 

 to which this new law leads, there is an obvious one notoriously 

 at variance with observation, — that no compression could raise 

 the temperature of air from the freezing to the boiling point of 

 water ; for, the greatest number we can substitute for §, will 

 always bring out i less than 180°, with r =i 32°. Hence, were 

 all the air which invests our globe condensed into a point, its 



* During the long period in which Mr. Ivory wrote on this subject, it 

 is curious to observe that, thous^h he is always right, and every one else 

 wrong, he is incessantly changing his creed without giving the reason. 

 Accordingly, this new law of condensation comes forth in February, 1827, 

 without the least hint that the law of July 1825, was either repealed, or 

 had ever existed. 



