420 Appendix to Dr Richardson's Observations 



gree being as nearly as possible equal to one of tbe scale at- 

 tached to the descending limb by the maker. As results such 

 as I have mentioned did not seem to be contemplated by the 

 inventor of the instrument, and as I conjectured that the very 

 low mean temperature of the air in February, March, and 

 April, might affect the indications of the instrument by greatly 

 contracting the coloured fluid, I did not print the register in 

 Franklin's Appendix. The abstracts now given, however, 

 serve to corroborate the deductions made from the observa- 

 tions on the radiation thermometer as to the greater effects of 

 the sun-light in spring in high latitudes, whether it be owing 

 to reflection from the snow or some other cause. Table VIII. 

 contains an abstract of the register for three months in which 

 the observations were most regularly made. Table IX. in- 

 cludes the months in which the observations were made only 

 on favourable or convenient days. From the crust which 

 forms on the snow in March, the radiation from it affects the 

 eyes more severely in March and April than at other times. 



TABLE VIII. 



Results of a Register of the Indications of Leslie's Photometer kept 

 at Fort Franklin in 1826. 



