48 



REPORT 1856. 



the bulb and rises in the wide bore, then the wide bore may be pointed off at differ- 

 ent temperatures like an ordinary thermometer ; but if under these circumstances 

 the mercury does not rise in the wide bore, then, in order to point off the wide 

 bore, the instrument must be laid horizontally in a dish of water, and compared 

 with a standard thermometer at different temperatures ; the extremity of the 

 mercury in the narrow bore being always kept at a fixed point. When the 

 wide bore has been pointed off, we may, by running the mercury along, find 

 what length of the narrow bore corresponds to a certain length of the wide 

 one, and thus be enabled to point off the narrow bore. In using the instrument 

 it should be kept nearly horizontal, and there is probably for each instrument a 

 small range of inclination, for every position within which its peculiar action holds, 

 but beyond which it is interfered with by gravity. Before graduating such an instru- 

 ment it should be ascertained whether it is likely to answer, and the best test 

 seems to be to lay it horizontal, exposing it to changes of temperature of the same 

 nature with those which it is intended afterwards to measure;— if its action be per- 

 fect, the mercury will eventually be found to have retreated into the bulb from Ihe 

 narrow bore ; but should it have stopped at any point, the action will only be 

 perfect up to that point. If this demands too much time, it may be tested by 

 repeatedly applying to the bulb of an instrument so placed a few drops of slightly 

 warmed water. 



On the Climate of Torquay and South Devon. By E. Vivian, M.A. 



Mr. E. Vivian, of Torquay, laid before this Section the statistics of the meteoro- 

 logy of Torquay and South Devon contrasted with those of the average of England, 

 as given in the Reports of the Registrar-General, to which he is a contributor. The 

 observations on which they were based extended from 1842 to 1856, but the com- 

 parative statement was confined to the last six years. The following was the 

 general summary : — 



He explained the principles upon which the cool summers and mild winters of 

 South Devon and Cornwall are to be accounted for, namely, the equable tempera- 

 ture of the sea with which the peninsula is surrounded. He had observed the 

 surface water in Torbay to be as much as 21 degrees above the minimum tempe- 

 rature of the air in winter, and 13 degrees below the maxim.um in summer. He 

 also accounted for the equable hygrometrical condition of the air by the same 

 cause — the temperature of the sea being frequently above the dew-point in winter 

 and below it in summer. He reviewed the inaccuracies in several medical pub- 

 lications, which had raised a prejudice against South Devon as a summer residence 

 as being too relaxing, while the exact contrary is shown by these observations. He 

 exhibited a set of his newly invented meteorological instruments for obtaining all 

 the really important elements of climate by one daily, weekly, or monthly obser- 

 vation, especially self-registering hygrometers ; one for the maximum and minimum 

 difference of the wet- and dry-bulb thermometers, the other for registering their 

 average difference during any period of time. 



