24 JForests and ^iain/alt. 



Influences of Temperature. 



ED. Western Horticulturist: Ordinary thermometers indicate the tem- 

 perature only at the instant of observation. Unless observed constantly the 

 duration of any degree of temperature is not shown. Practically, duration is a very 

 important matter in determining influences of temperature. Suppose that a hot-house 

 is to be managed, or nursery stock to be moved. The thermometer may indicate 

 10° on the morning of any day about the middle of October, and endure at that for 

 only three or four hours. Less damage would be done to living plants than when, 

 two weeks later, the mercury shows 15° or 20°, but remains at that for two days. 

 In the latter case the earth and plants become cooled so as to be constantly freezing ; 

 in the former case the latent heat would not all be taken from the ground to permit 

 freezing so soon. The earth in the first instance would not freeze so as to injure 

 potatoes, flower-roots, etc., when in the latter case they would be entirely 

 destroyed. 



Extremes, not means, are the practical features of climate. The fact that the 

 average temperature of May is 50° is not so important a fact to horticulturists as 

 that the cold of May is 25° often as late as the 25th of the month. The probability 

 of excessive heat or untimely frosts must modify the action of gardeners, florists and 

 farmers in planting, and nurserymen in the moving of articles liable to injury by 

 extremes of temperature. 



In view of these and kindred facts we would suggest to scientists the desirability 

 of a self-registering thermometer, one that will show the temperature at any and all 

 times, in all its fluctuations, variations and extremes. Is not such an instrument 

 practical ? 



Ithaca^ Wis. \ A. L. Hatch. 



Forests and Rainfall. 



IN the November number of the Horticulturist, page 338, Dr. Housley refers 

 to the fact of an abundance of rain in the timbered regions of the Rocky Moun- 

 tains, while east of there, on the great plains, very little rain falls, and there is no 

 timber ; hence the inference that timber is the canse of rain. I would infer that rain 

 is the cause of timber. 



I do not think it necessary to go into an argument to support such a theory, but 

 simply state this as being the more rational conclusion. I would advise, and most 

 earnestly advise, the planting of trees for effects which we are certain of, such as 

 wind-breaks, use of timber and wood, ornament, modifying the rigor of the climate, 

 both summer and winter. Statistics of the quantity of rain in the early settlement 

 of our forest country, and after it had become cleared of its forests, would be more 

 conclusive than many suppositions which we often see. 



Muscatine, Iowa. Suel Foster. 



