306 APPENDIX. 



bodies, and the changes they undergo whilst under our obser- 

 vation, and which may be considered a reversal of the laws 

 by which they were originally formed, is an investigation full 

 of interest in itself, and will probably give collateral aid to 

 other and higher branches of meteorological inquiry." 



F. 



General Tables of Meteorology . 



In the compilation of the following Tables I have selected only from 

 the records the noon, midnight, and mean readings of the Barometer, 

 the maxima, minima, and mean of Thermometers, and similar data on 

 all other points. 



From the autumn of 1852 to the summer of 1853 the records used 

 are those of the Observatory on shore, and comprise hourly observations, 

 when magnetic disturbances did not call for them more frequently. 



The matters registered on shore coincided so nearly with those made 

 by the best instruments on board, read two-hourly, that I had no mis- 

 givings as to the perfection of the observations, and consequently of 

 the attention of those entrusted with their record. 



This was the more material in the second season; and having a 

 perfect value resulting from a proof of fifteen standard thermometers, 

 mercurial from 40 upwards, and spirit from 63'5 upwards, the 

 best, or that representing the mean of all, was adopted as the standard ; 

 the others (reduced to thirteen) were also registered, as before, in order 

 to correct any irregularities, under an inverted boat suspended at the 

 Driver boom-end. 



The whole of these thermometers, furnished partly from Greenwich 

 by Mr. Glaisher, and partly from the Kew Observatory, have been 

 safely returned to this country, and are now valuable standards of 

 comparison for very low temperatures. 



