1873-] TEMPERATURE OF FORCING-HOUSES. 215 



to my satisfaction. So far from this being my intention, I was not aware until 

 I read his paper in the April number that I had unwittingly substituted the 

 word Peas for Hamhurgs. I did not need, nor would it serve any purpose of 

 mine, to alter his text. His next accusation is, that I made him appear to say 

 that we might haul out our boilers and pipes. I had no intention, nor did I 

 even make him appear to say so, but that was what I inferred from his state- 

 ments, and so far as I am concerned I could maintain a temperature of 45° 

 without them ; but we will see by-and-by why J. S. cannot dispense with his. 

 Again, he takes exception to my saying that he advocated a difference of 55° in 

 6 hours ; he maintains that there is 18 or 20 hours allowed for the subsidence of 

 the thermometer. "Would he be surprised to learn that I counted from morn- 

 ing till noon, and I hold I am still right ? If the qviestion raised by J. S. had 

 been regarding the best way to keep Vines in health, I woidd very likely have 

 supported him, especially if he had not drawn the line at such extreme points. 

 But it must be remembered that we are dealing with forcing-houses, and that 

 very ,many employers require fruit at a given time, hence the information most 

 desir^ I by many is the highest safe temperature to insure success. J. S. quotes 

 an extract from Dr Lindley's ' Theory and Practice of Horticulture,' to prove 

 that the temperature varies about 55° in 24 hours in a vine-growing country. I 

 need not quote the extract in full. " At Candahar, on the 30th of June, a tra- 

 veller (Mr Atkinson) saw donkeys laden with panniers of fine purple grapes." 

 But where is the account of the cold from ? from the desert near Shikapore, 

 where the traveller was on the 7th March. Again this same traveller 

 on reaching Cabul in August found the bazaar filled with delicious grapes 

 in astonishing profusion. Now the extract referred to never says there 

 were even Vines at Shikapore, but at Candahar, 200 miles farther north, 

 and at Cabul 500 miles farther north there is abundant evidence of grapes. 

 Now where in all the world would one expect extremes of temperature if not in 

 an unsheltered desert ? Here is indeed a wide range of country to gather grapes 

 from. We have no evidence of cold nearer the market where grapes are seen 

 than from 200 to 500 miles, and that evidence is rather loose. "Frost seemed 

 to be in the air, and they were grilling the day before at Shikapore." If these 

 travellers had not more reliable indications of frost than that the night was 

 cool and bracing, is it not quite possible that men that were grilling the day be- 

 fore might think the night chilling, although the temperature was very much 

 above the freezing-point ? Suppose we grant that it seemed to be freezing, many 

 a hill, and dale, and sheltered nook, might intervene between Shikapore and 

 Candahar, where Vines would be perfectly secure from the extreme cold felt in 

 the desert. Is it to be inferred that because Candahar and Cabul were farther 

 north it would be still colder in these districts ? Such is not the case in this 

 country, as the following will prove. At Garvald, in Peeblesshire, in the winter 

 of 1865, we had a storm of frost and snow of seven weeks' duration, the ther- 

 mometer registering, night after night, in February from 20° to 30° of frost, and 

 while this storm held the ground hard and fast at Garvald, they were busy 

 ploughing between Edinburgh and Glasgow, 25 miles farther north. I may 

 add that, for the last five winters, a Negretti in the most exposed part of the 

 grounds here has never registered more than 15° of frost, and that only on one 

 or two occasions. In fact 9° of frost is considered extreme here, and at a 

 place only one quarter of a mile from where I sit, they have upon all occasions 

 3° more of frost than what we have here. I think the above will show that there 

 might be abundance of grapes in the markets of Candahar and Cabul, even 

 though it were freezing in the desert in March ; which from the evidence is very 



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