Lieut.-Col. Sabine on some Points in 



• I see Mr. Cayley has amended his paper of November 1844. 

 If he would amend it a little further, it would not be amiss. He 

 has now made p a prime number instead of any odd one : is 

 made of the second instead of the general form. In the ex- 

 pression of $ y .r, or rather <p x', he should have had the trans- 

 formed function x' = j-r-, not «,(3a function of 0. Moreover, 

 ] • WV t i i 



Some other amendments are greatly wanted. When x has a 

 determinate value, x 1 should have one also, since /3 is a known 

 function of 0. And if we know what value to assign to x, we 

 should have the value of x', which is the complete function. 

 I have no room to enlarge, and as Mr. Cayley has done no- 

 thing which invalidates what I have done, it is unnecessary. 

 Gunthwaite Hall, Dec. 12, 1845. 



VIII. On some Points in the Meteorology of Bombay. 

 By Lieut.-Colonel Sabine, R.A., FM.S.* 



[With a Plate.] 



IN a communication which I had the honour to make to the Sec- 

 tion at the York meeting of the British Association, on the sub- 

 ject of the meteorological observations made at Toronto in Canada 

 in the years 1840 to 1842f, I noticed some of the advantages which 

 were likely to result to the science of meteorology, from the resolu- 

 tion of the barometric pressure into its two constituents of aqueous 

 and of gaseous pressure. It was shown that when the constituents of 

 the barometric pressure at Toronto were thus disengaged from each 

 other and presented separately, their annual and diurnal variations 

 exhibited a very striking and instructive accordance with the annual 

 and diurnal variations of the temperature. The characteristic fea- 

 tures of the several variations when projected in curves were seen 

 to be the same, consisting in all cases of a single progression, having 

 one ascending and one descending branch ; the epochs of maxima 

 and minima of the pressures being the same, or very nearly the 

 same, with those of the maxima and minima of temperature ; and 

 the correspondence in other respects being such as to manifest the 

 existence of a very intimate connexion between the periodical varia- 

 tions of the temperature, and those of the elastic forces of the air 

 and vapour. The curve of gaseous pressure was inverse in respect 

 to the other two ; that is to say, as the temperature increased the 

 elastic force of the vapour increased also, but that of the air dimi- 

 nished, and vice versa ; and this was the case both in the annual and 

 the diurnal variations. 



* Communicated to the Mathematical and Physical Section of the British Asso- 

 ciation for the Advancement of Science, at the Cambridge Meeting, 1845. 

 t See Phil. Mag., vol. xxvi. p. 94. 



