HUTCHISON'S OBJECTIONS, WITH REPLIES. 465 



are occasiqned exclusively by the same cause that produces 

 clouds and rain, and which you say is an upward vortex of 

 air, produced and maintained by heat evolved during the 

 condensation of invisible vapor into clouds. Now when it 

 is considered that the amount of rain which falls in a given 

 time, and the amount of heat evolved during its conversion 

 from invisible vapor into clouds, decreases from the equator 

 to the poles, your hypothesis cannot be reconciled with the 

 fact, that the range and fluctuations of the barometer, in- 

 stead of decreasing, (as would be the case if your hypothe- 

 sis were correct,) rapidly increases from the equator to 

 about the 60th parallel of latitude, and again decreases 

 from the 60th parallel as we advance towards higher lati- 

 tudes. That this is the case, is evident from the following 

 table : l 



Mean annual range of the barometer. 



Quito, . S. lat. 13 . . about 1 line. 



Peru, . . . . . 5 of an inch. 



Calcutta, . . N. lat. 22 35 . . J of an inch. 



Kathmander, . lat. 27 30 . .85 an inch. 



Capital of Japan, lat. 32 43 . . .85 an inch. 



Paris, . . lat. 48 50 1| inches. 



Great Britain, averaged . . .2 inches. 



Petersburg, . lat. 59 56 . 2\ inches. 



Melville Island, . lat. 74 30 . . 1.86 do. 



1 According to my theory, undoubtedly the great barometric fluctuations 

 are produced solely by the caloric of elasticity evolved by the condensation 

 of vapor in storms. 



I have made the calculation how much the barometer ought to fall under a 

 cloud of a given height, with a given dew point, that is, with a given steam 

 power in the air, and as this calculation is made on acknowledged scientific 

 principles, it must stand, unless the principles themselves fall. The objec- 

 tions leave this fundamental principle unimpeached. No notice has been 

 taken of it. 



It is true, indeed, that my u doctrine cannot be reconciled with the fact, 

 that the range of the barometric fluctuations rapidly increases from the 

 equator to about the 60th parallel of latitude." And if this were really a fact, 

 59 



