37 



46o, 49°. The reports from various stations in the State to 

 the Weather Bureau at Boston for Septembers average con- 

 siderably lower than this, thus : in 1896 from reports of 27 

 stations there were 10 under 32*^, 25 under 40°, the lowest 

 being 30°. In 1897 of 24 stations, there were 2 under 32°, 

 21 under 40"", the lowest being 31. With the same ratio 

 for the entire State, it appears therefore that there would be 

 freezing weather in a considerable number of towns every 

 September, and that light frosts would be liable to occur in 

 almost every place ! 



The difference in the mean temperature of the summer 

 months is generally insigniticant. In 1895 there was an 

 increase of 2° l)etween that of June and of July, and 2° more 

 between July and August. In 1898 the increase between 

 the mean of June and of July was 6° plus, and between 

 July and August but eight-tenths of a degree. Between 

 August and September, however, there is usually a decrease 

 of 8°, and between September and October 12°, the mean 

 tem[)erature of October being on an average 20"- below that 

 of August ! 



Growers of roses find a temperature of not lower than 

 55° at night and 70"^ to 75° by day the best for certain va- 

 rieties, as Brides and Bridesmaids. If the temperature 

 should fall 10° lower at night, the growth would be checked, 

 few or no roses produced, and the plants be liable to mildew 

 and black s[)ot and to change color. That is to say, the 

 sudden change from an unusually low temperature at night 

 to a high one would be prejudicial to the health of the plant. 



If a plant under glass is injuriously affected by a fall of 

 10° below the usual temperature, it is quite likely that an 

 average fall of 20° in the open air would diminish the vital- 

 ity of many kinds of leaves, and that the sudden change 

 from very cool nights to very warm days would be likely 

 to slowly disintegrate the chlorophyll and induce the autum- 

 nal tints even when there were no frosts I Notes on Frost, 

 by Prof. E. B. Garriott, Weather Bureau, Washington, 



