422 



NATURE 



[July 20, 19 16 



about E.S.E. to W.N.W. The colours varied from 

 bright green and purple to a deep red round the 

 edges. The display continued all the evening, and 

 at 10 p.m. it worked to the N.N.W., appearing to 

 reach the northern horizon. 



June 18, 9 p.m. — Barometer 29-658 in., tempera- 

 ture 278° F., wind S.W., 9. Snowstorms through- 

 out the day with fierce S.W. gales. Brilliant aurora 

 visible between breaks in the clouds. 



Mr. Henderson reports : — 



June 16, 8.40 p.m. — Very pale glow low down to 

 the south. 



June 17, 5.30 to 5.40 p.m. — Very vivid blanket form 

 of aurora in the zenith, then a large red bank to 

 the north-east very low and close, and red to the 

 north ; red fades and glow remains. 



10 p.m. — Streamers and blanket form, and ring to 

 the west and north. 



The "atmospherics" heard in the wireless receiver 

 varied in strength from o to 5 at intervals of about 

 thirty minutes. 



June 18, 9.20 p.m. — Sky nearly overcast, but bright 

 glow visible overhead for a few minutes. 



Although the auroral and wireless data appear to 

 lack correlation, it may be of interest to note the 

 circumstances under which the long and short waves 

 (2000 m. and 600 m.) from Awanui, near Auckland, 

 were received at Macquarie Island. 



Of the six nights when both wave-lengths were 

 recorded, the 600-metre wave was much the stronger 

 on three nights when no aurora was seen ; on two 

 nights when the aurora was reported the longer wave- 

 length was the stronger. On the remaining night the 

 longer wave was again the stronger, but the sky 

 was overcast and the moon approaching the full. 

 An aurora, if there had been one, could scarcely have 

 been seen in the circumstances. 



H. A. Hunt 

 {Commonwealth Meteorologist). 



Meteorological Bureau, Central Office, 

 Melbourne, May 24. 



The Utilisation of Waste Heat for Agriculture. 



In the cheap generation of electricity the great 

 problem must be how to secure and utilise by-pro- 

 ducts. With steam-driven stations the chief by-pro- 

 duct is an abundant supply of hot water from the 

 condensers, which in this country is looked upon as 

 a nuisance to be got rid of as easily as possible. 

 Would it not be possible to make use of this low- 

 grade heat for agricultural purposes, so supplementing 

 our all too scanty summers? 



Power-houses burning 1000 tons of coal and up- 

 wards per week are quite common, and something 

 like half of the heat generated by the coal is absorbed 

 by the condensing water. It might be possible to 

 heat fields by running the warm water through 

 ditches, or perhaps better results would be obtained 

 by running it through pipes buried in the ground. 

 By this means large areas of land might be stimulated 

 to produce much greater crops than have hitherto 

 been found possible. It may be urged that the 

 majority of existing power-houses are not in agri- 

 cultural districts, so that the proposed experiment is 

 not possible except in a few cases. To this one may 

 reply that, in the near future, many large stations 

 will be put down to supply current in bulk to vast 

 areas. With the high voltage used for them the 

 location of the power-house becomes a matter of wide 

 choice, and it would be possible to put them in agri- 

 cultural districts if this should prove financially worth 

 while. The views of readers of Nature on this point 

 would be of interest. C. Turnbull. 



Electricity Works, Tynemouth, June 29. 



NO. 2438, VOL. 97] 



SCIENTIFIC HORTICULTURE.^ 



''T^HE periodic reports of the experiments con- 

 -*- ducted by the Duke of Bedford and Mr. 

 Spencer Pickering at Woburn are always sure of 

 a warm welcome by scientific horticulturists. It 

 is true that these reports often give rise to con- 

 troversy, and sometimes disturb the tranquillity 

 of established horticultural belief; but if horti- 

 culture is to be a progressive craft both contro- 

 versy and loss of tranquillity are to be welcomed. 



The present (fifteenth) report covers a wide area 

 of ground and records the results of observation 

 and experiment on many subjects of importance 

 to the fruit-grower. Among these subjects are : 

 the fruiting of trees in consecutive seasons, injury 

 to tree-roots in planting, ramming the roots cf 

 trees at planting-time, modes of planting and 

 pruning. The observations on the alternation of 

 fruitfulness and relative unfruitfulness support in 

 a measure the view commonly held by fruit- 

 growers that such an alternation exists, although 

 the authors are inclined to attribute it rather to 

 the effect of external conditions — for example, 

 spring frosts — than to an internal rhythm. 



For our part, we are convinced that if the 

 alternation is to be ascribed — as in fact it may 

 well be — to external conditions, those con- 

 ditions are more subtle and complex than 

 the authors' hypothesis suggests. As to the 

 fact of alternate fruitfulness and barrenness 

 exhibited by certain varieties of apple there can 

 be no doubt. One of the most striking exarnoles 

 was published some years ago by the Dominion 

 Horticulturist (Canada), and was cited in the 

 Gardeners' Chronicle. The numbers are so re- 

 markable that they may be repeated here. A 

 single tree of the apple Wealthy yielded the fol- 

 lowing amounts of fruit : — 



Year loih nth 12th 13th 14th 15th i6th 



Gallons of fruit 33 052 2 93 o 1 1 ^ 



Year 17th i8th 19th 20th 21st 22nd 



Gallons of fruit 22 96^ i| 75 5 118 



Such a record establishes the fact of alternation 

 of fruitfulness once for all, and it is the business 

 of the scientific horticulturist to discover the ex- 

 planation why certain varieties exhibit this alter- 

 nation and why others do not. 



Although we are far from being able to give a 

 sufficient explanation of this alternate fruitfulness 

 and barrenness, yet it is by no means impossible 

 to see the direction in which the explanation is 

 to be sought. 



Kleb's brilliant investigations show that the 

 nature and amount of the raw and elaborated food 

 materials at the disposal of a plant determine the 

 formation of vegetative or reproductive tissues. 

 In such fruit-trees as the apple the blossom buds 

 are laid down early in the preceding year. If at 

 the period of their development there is a large 

 demand on the part of the setting and maturing 

 fruit for certain food materials, and if the supply 



1 Woburn Experimental Fruit Farm. Fifteenth Report. 

 (London : Amalgamated Press, Ltd., 1916.) Price 25. ■^d. 



Pp. 83. 



I 



