380 



THE FARMER'S MAGAZINE. 



in 1669, advised the farmers of his day {System of 

 Agriculture), that " Some sow barley in March 

 some in April, others not until May." There are, 

 _ in fact, many agriculturists now alive, who will re- 

 member that, in their boyhood, no one thought of 

 sowingbarley until March or April. This dread of ex- 

 posing barley to a low temperature was a natural 

 conclusion of our forefathers. They well knew it was 

 the native of a warmer climate than ours. It was 

 cultivated, they learnt from the best authority, in 

 Palestine, so early as the year 1491 a.c. {Exodus ix. 

 31). They were aware that the Romans imported it 

 from the shores of Africa and Spain. Barley will not, 

 however, succeed in other than temperate climates. 

 It will grow indeed under the equator, but only at 

 such elevations above the level of the sea as com- 

 pensate for the effects of latitude : even at 3,000 or 

 4,000 feet it is there not worth cultivating. Hum- 

 boldt noted that on the great Himalayan chain it 

 succeeds as high as 14,707 feet, and another variety, 

 called Ooa, even much higher ; and in the Thi- 

 betian Highlands, wheat succeeds extremely well 

 up to 12,022 feet. The fear of exposing barley to 

 a low temperature has, however, long since ceased. 

 We are all aware that in some districts it has be- 

 come almost as much a winter crop as wheat, and 

 that the quality of seed produced from early-sown 

 barley is very superior. _The Northern farmers, too, 

 have found that the barley grown in the South of 

 England is the best for seed ; that so far from the 

 crop it produces being more injured by the cold of 

 our more northern spring nights, it in fact ripens 

 earlier than if the barley ripened in the North is 

 employed for seed. 



Owing to barley being capable of maturing its 

 seeds in ninety days, it can be grown as far North 

 as 70 degs. ; for, in Lapland, during their short 

 summers the average temperature is greater than 

 during the same periods in portions of Scotland. 

 It will not generally ripen in a lower mean tem- 

 perature than 56 degs. In our island the height 

 above the sea at which it may be successfully cul- 

 tivated extends from about 1,000 feet in the South 

 to 800 feet in the Eastern side of Scotland, and to 

 600 feet on its Western, but not much above the 

 level of the sea in the North. The creeping as it 

 were of the barley fields up the sides of our hills 

 has been steady, but gradual ; it is now indeed 

 successfully cultivated in portions of our island at 

 elevations which our forefathers would have deemed 

 impossible. 



It is evident indeed that our barley cro])s are not 

 an exception to the general rule that plants are 

 benefited by being exposed to a lower temperature 

 during the night than that of the day ; nay, that such 

 a variation is almost essential to their prosperity. 

 The remark is not confined to our native produc- 



tions. The tea plant of China is exposed to, and 

 is at least uninjured by, very severe frosts. The 

 vines of the wine-producing countries bear a similar 

 low temperature with advantage. The most 

 flourishing vineyards of some districts of France 

 are those with a northern aspect. The same re- 

 mark very commonly applies to our own woods. 



There is, then, little doubt but that a periodical 

 lowering of the temperature, by causing rest to the 

 plant, promotes its vigour ; just as exposure to 

 considerable and long- continued heat by over- 

 exciting, finally deadens the energies and reduces 

 the vigour both of plants and animals. 



It is difficult for the farmer to prove these things 

 by any easily-accomplished experiments. Here 

 the gardener possesses a considerable advantage : 

 his trials can be readily made under cover, secure 

 from the many disturbing occurrences of the field. 

 Some very useful experiments in this way have re- 

 cently been recorded by Dr. Lindley {Gardener's 

 Chronicle, 1859, p. 312): they were made in the 

 Chiswick Garden of the Horticultural Society. 

 Certain plants were placed for several weeks in a 

 stove with a high night-temperature, supposed to 

 average 69 degs. Their rate of growth both by 

 day and night was carefully recorded. The results 

 were as follows, the lengths attained by the plants 

 being given in inches : 



By Night. By Day. 



Fig 9'60 9-92 



Willow 19-08 21-55 



Passionflower.. 36*20 35-85 



Vine 34-15 34-45 



99-03 101-77 



So that in high temperature they grew as fast by 

 night as in the day But when these and other 

 plants were grown in the open air exposed to our 

 low night-temperature, the results obtained were 

 very different. This is clearly enough shown in 

 the following table of their growth : 



By Night. By Day. 



Fig 1-63 6-80 



Willow 3-77 9-94 



Hop 42-02 100-53 



Vine 2-34 4*20 



Scarlet runner. . 23-11 97-72 



Jerusalem arti- 

 choke 8-23 22-25 



Gourd 21-23 48-05 



102-33 289-49 



This experiment was repeated with similar results. 

 Thus we see, as Dr. Lindley adds, that ])lauts ex- 

 posed to natural circumstances only made one inch 

 of growth by night, while they made three by day ; 

 but that, on the contrary, under bad artificial treat- 

 ment they grew equally day and night. If, indeed, 

 we consider a little what the natural habits of 



