Book III. 



METEOROLOGICAL MACHINES. 



S93 



SuBSECT. 3. Meteorological Machines. 



1487. The garden-indicators of weather differ from those in common 

 use only in two instances, that of the registering thermometer and regu- 

 lating thermometer. The barometer, hygrometer, rain-gauge, and vane 

 or Eolian index, may all be usefully employed in gardening, (1278.) 

 and should be fitted up in and about the gardener's office. The rain- 

 gauge and vane may be placed on the roof of his office, and should 

 communicate with the interior by means of tubes and machinery, the 

 detail of which is perfectly known to opticians, and such as fit up ap- 

 paratus of this kind. 



1488. Six's registering thermometer (Jig. 216.) is so contrived as to 

 indicate the extreme points to which it falls or rises in the course of 

 the day or night, and is, therefore, particularly useful as a check upon 

 the working gardeners, who have to attend to the fires, or steam, &c. of 

 hot-houses in the winter time. In the open air it is also a very useful 

 instrument, by pointing out the extremes of temperature. (iVicZt. 

 Encyc. art. Thermometer.) 



216 



