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Dr. H. Franklin Parsons on 



saucer is inverted. I have since thought that it would have been 

 better if the pipe for the shallower thermometer had been placed 

 obliquely, sloping to the north, so that the bulb of the thermo- 

 meter should have been at the depth of a foot, and have had the 

 earth and grass directly above it. The readings were taken once 

 a week, on Sunday mornings between 9 and 10 a.m. ; the maxi- 

 mum and minimum air-temperatures during the preceding week 

 being taken at the same time. These were taken by a Six's ther- 

 mometer hung against a north wall of my house. The readings 

 of this thermometer have been compared, by immersion in a 

 bath, with those of the earth thermometers, and corrected ac- 

 cordingly, so that they correspond to about 1° F. The average 

 of daily observations would no doubt have given a truer approxi- 

 mation to the mean temperature of the week, but frequent absences 

 from home in the early part of the year prevented my attempting 

 observations more often than once a week. The mean temperature 

 of the year (48-G°) thus obtained is about the same as at Green- 

 wich, viz., 48-3°; but the weekly readings are higher than the 

 Greenwich means in summer and lower in winter. 



The results of my observations are given in the accompanying 

 table and diagram. 



