VOL. XL.] 



PHILOSOPHICAL TRANSACTIONS. 



197 



In the table c may be seen the sums of the heights of the barometer and 

 thermometer for each year ; as also the mean heights corresponding to each day. 

 For the whole last 6 years, the mean height of the barometer, referable to 

 each day of the said 6 years, is 29 inches 73 dec. differing qnly, 03 parts from 

 that of the former 6 years, which was 29 inches 70 dec. And likewise the 

 mean height of the thermometer for each day of these last 6 years, is found 

 to be 50 inches 1 2 dec. differing only ,04 parts from that of the former 6 years, 

 which was 50 inches 1 6 dec. showing a remarkable uniformity. 



S. Poleni adds some observations on the declination of the magnetic needle. 

 In April 1733, he found by repeated observations, that the declination was 134. 

 degrees westwards. On the last days of the year 1736, he found it 13f de- 

 grees. If therefore what has been already said of the declination of the needle, 

 in Phil. Trans. N°42J, be compared with this, it will appear, that the declina- 

 tion for the 3 first of these 6 years increased more than it did for the 3 last. 



