I873-] TEMPERATURE OF FORCING-HOUSES. 153 



expressed no such opinion, nor even insinuated anything so absurd. 

 Again he says, "I fear ' J. S.' is going to let his craft adrift altogether. 

 A difference of 55° in six hours ! " My words were, " If the tempera- 

 ture of a vinery must be kept low enough at night to arrest perspiration, 

 it means that Muscats that have been allowed a temperature of 90° or 

 100° during a sunny day, when they are perhaps in bloom, must be 

 treated to a temperature of 50° at night, to fall maybe to 45° before 

 sunrise," thus allowing eighteen or twenty hours for the subsidence of 

 the thermometer, taking its maximum at noon. Then, again, "D. J." 

 makes me to say that I have " proved that Muscats will set like Peas 

 in a temperature of 60°." My words were, " Will set as thick as Ham- 

 burg s in a temperature of 60°," &c. I think we may be permitted to 

 doubt both the '' facts " and intentions of one who deals in such an 

 unscrupulous manner with his opponent's text. But let us hope that 

 as *' D. J.'s " literary experience improves, his knowledge and discretion 

 will improve also. His paper shows abundantly that there is a want of 

 information on the subject of temperatures in regard to plant life. In 

 my last I referred chiefly to experience, and will do so again ; but for 

 the sake of those of your readers who have not such books at hand, 

 and who would like further evidence on the matter, allow me to give 

 the following extracts from Dr Lindley's 'Theory and Practice of 

 Horticulture ' on the subject of low night temperatures for the 

 Vine : — 



"In no part of the world are the Grapes more dehcious than in Candahar 

 and Cabul. On the 30th of June, this traveller (Mr Atkinson) saw donkeys 

 laden with panniers of fine purple Grapes ; and at the same time the paper on 

 which he was writing curled up and became as crisp as if it was before a blazing 

 fire. When he reached Cabul, in August, he found tlie bazaar filled with 

 delicious Grapes in astonishing profusion. But what sort of nights had the 

 troops in the spring of the year, when the Vines were growing and flowering 

 and preparing themselves to bear fruit ? On the 7th of March, near Shikapore, 

 200 miles south of Candahar, and above 500 south of Cabul, in the desert, we 

 are told that the march took place on ' a brilliant starlight night ; frost seemed 

 to be in the air, it was so cool and bracing ; after midnight the servants made 

 up a blazing fire, for the north wind was blowing bitterly cold, and the traveller 

 was glad of hot brandy-and- water.' Nevertheless, the day before, Mr Atkinson 

 had been grilling at Shikapore ; and the march was over level plains, and not 

 among the mountains. Two days afterwards the weather is described as being 

 oppressively hot at mid-day; then on the 19th March there was a hail-storm at 

 night, and the air was ' cold and bracing,' and so on. 



" Here, then, in a country totally different from the islands of the Mediterranean, 

 where the Grapes are famous for their excellence, we have violent variations in 

 temperature between day and night in the month of March, when the Vines are 

 shooting ; the air is cold and bracing by night, and the sun is grilhng by day." 



Then again, in the same page, Dr Lindley gives the extreme fall of 

 temperature during the night in the interior of tropical Australia, as 



