72 



the thermometer does the temperature, and which may 

 be as easily read off and understood. Simmons' hy- 

 grometer, recently introduced to the notice of horti- 

 culturists, professes to supply this desideratum ; and 

 though, perhaps, not a sufficiently accurate instrument 

 for purely scientific purposes, yet, as simply and clearly 

 indicating what is at least an approximation to the 

 existing degree of atmospheric humidity, it is to be re- 

 garded as a useful garden hygrometer. By it, the 

 degree of dryness or humidity is indicated on a dial- 

 plate, by means of a moveable arm resembling the 

 hand of a clock. The dial-plate is marked off into de- 

 grees, expressing the amount of moisture in the air, 

 between what is observed when the instrument is 

 plunged in water on the one hand, and exposed to ex- 

 cessive dryness on the other. As my own experience 

 of this instrument, though favourable to its use, is still 

 but limited, I cannot do better than introduce here the 

 following remarks of Mr. Beck, of Isleworth, a very 

 successful cultivator of plants, and one who has had 

 considerable experience in the use of these instruments. 

 It will be observed that Mr. Beck's standard for the 

 orchid-house will be about suitable for cucumbers.* 

 Mr. Beck observes, " The skilful gardener, observing 

 the pointer to advance with dryness and return with 

 moisture, will soon form a standard for himself, by 

 which to regulate his stove, greenhouse, &c.; still 

 some general scale is desirable. Two conditions must 

 be carefully observed : 1. The instrument must nei- 

 ther be hung in the sun, nor where it will be liable to 

 get wetted or saturated. 2. It must not be subjected 

 to greater heat than is suited to vegetable life. For 

 the six months commencing with August and ending 



* Gardener's Chronicle 1847. 



