120 



REMARKS ON SURFACE TEMPERATURE. 



Similar observations were made at the same time at Bodmin, by Capt. 

 Liddell, the only difference being the substitution of a screen of muslin for 

 the straw matting used by me. The following extract from his register is 

 sufficient for all purposes of corroboration and comparison : — 



The results of these observations are conspicuously shown on the 

 accompanying diagram. It will be seen, as might be expected, that the 

 sheltering efficacy of muslin is not equal to that of straw matting ; but the 

 amount of protective influence of so slight a material is worthy notice. 

 The average difference between the sheltered thermometer and that in the 

 shed was for Truro 1-22", for Bodmin 1-40''; the greatest difference for Truro 

 and also for Bodmin S-O". 



The following record of a few observations made by Mr. Whitley, at Pen- 

 arth, near Truro, 200 feet above mean sea level, shews the effect of a slight 

 covering of straw over large Broeoli plants during a period of hoar frost. The 

 thermometer amid the Broeoli was on a level with the heart of the plants. 



