BY THE KEV. K. F. WHEELEE, M.A. 261 



be surprised with showers, and it will enable him to count upon 

 the continuance of sunshine on almost every occasion of such 

 indications. We say almost, for there are occasions, rare, it 

 must be admitted, when the hygrometer fails to announce the 

 coming change ; but this unavoidable defect may easily be sup- 

 plied by what should always be its companion instrument— the 

 evaporation guage. 



"For our own part, we may state, that since we have set 

 up these instruments, and studied them, we have never been 

 ' caught in a shower' without an umbrella, nor have we been 

 inconvenienced by carrying an umbrella without having to use 

 it. This is rather important ; for a good umbrella costs more 

 than a good hygrometer, and it is quite certain that umbrellas 

 are more injured by carrying than by use as a shelter from 

 showers. Of course, to the farmer at haymaking time, and 

 during harvest, the use of such a monitor would be invaluable." 

 The hygrometer, it will be as well to remark, must for this pur- 

 pose be placed out of doors ; hence the almost uselessness of all 

 attached to what are called farmers' barometers. As regards 

 other uses of the hygrometer Mr. Glaisher makes some valuable 

 suggestions in his Hygrometrical Tables* 



" The use of the instrument in the requirements of the Sick 

 Chamber are scarcely to be over-rated, and will be at once ob- 

 vious to all who know that the comfort of the patient is depen- 

 dent, not so much on the temperature, as on the hygrometric 

 condition of the air 



" If the air be too dry, that is to say, if the difference of the 

 readings of the thermometer is very considerable, it will be ne- 

 cessary to expose water in some shallow vessel, so that the eva- 

 poration from it, mixing with the air, will cause a greater degree 

 of humidity. 



"If, on the contrary, the air be too moist, or should be re- 

 quired to be remarkably dry, all water must be covered over or 

 removed, and the required degree of dryness obtained, either by 

 raising the temperature, or by placing in the room sulphuric acid, 



* Hygrometrical Tables adapted to the use of dry and wet bulb thermometer, price 2s. fid. 

 Taylor and Francis, London. 



