i68 



NATURE 



[April 20, 19 16 



Much attention has been paid in America to preven- 

 tion of damage by frost to fruit and vegetable crops. 

 The methods are based either on the prevention of low 

 temperatures, or the protection of frosted plants from 

 too rapid warming. The Geographical Review for 

 February, 1916 (vol. i., No. 2), contains an illustrated 

 article on the subject. Low temperatures are pre- 

 vented by small fires, oil-pots (Fig. i), steam pipes, or 

 even by hot water in irrigation ditches. Apparently no 

 method to utilise electrical energy has yet been devised. 

 To reduce loss of heat by radiation, artificial clouds 

 are caused by fires of wet straw, but lath screens 

 are most effective, though too expensive as a rule. 

 Mixing the air by some mechanical means to prevent 

 ground frost on clear, calm nights would be useful, 

 but no practicable method has been discovered. Rapid 

 warming or "defrosting" is prevented by the same 

 means used to check radiation, and also by spraying 

 the plants with water at about 32° F. just before sun- 

 rise. This coats the plant with ice, which must be 

 melted before warming can begin. As a result, warm- 

 ing is said to be gradual. All these, and other 

 methods, are, of course, intimately associated with 



Photo. 



Fig. I.— Oil pots in operation in an orchard at Grand Junction, Colorado. The oil pots hold seven 

 gallons each and burn crude oil in amounts depending on the heat required. 



accurate weather forecasts, since the preventive 

 measures are too elaborate and expensive to be 

 employed unless required. 



A SUMMARY of temperature, rainfall, and duration of 

 bright sunshine in the United Kingdom for the first 

 quarter of the current year, comprised in the thirteen 

 weeks from January 2 to April i, 19 16, has been issued 

 by the Meteorological Office The mean temperature 

 for the period was in excess of the average in all dis- 

 tricts, except the south of Ireland, where it was normal ; 

 the greatest excess was i-6° in the east of England. 

 The absolute maximum temperature ranged from 53° 

 in the north of Scotland to 65° in the east of Scotland, 

 and the thermometer failed to touch 60° in several dis- 

 tricts, including the south-east and south-west of Eng- 

 land. Rainfall was in excess of the average in all 

 districts over Great Britain, except the west of Scot- 

 land, and there was a deficiency of rain in Ireland. 

 The greatest excess was 177 per cent, of the average 

 in the east of England, while in the south-east of 

 England the fall was 161 per cent, of the average, and 

 160 in the Midland counties. In the east of Scotland 

 the rainfall was 141 per cent, of the average, while in 



NO. 2425, VOL. 97] 



the west of Scotland- the fall was only 88 per cent. 

 In the north and south of Ireland the fall was respec- 

 tively 93 and 92 per cent, of the average. The rain- 

 days were everywhere in excess of the normal, the 

 number in the period ranging from 72 in the south of 

 Ireland and 71 in the north of Scotland to 56 in the 

 north-east of Eng'and and in the Midland counties. 

 The duration of bright sunshine was generally de- 

 ficient. The exceptional warmth of January and the 

 heavy rains of February and March would consider- 

 ably influence the quarter's results. 



Mr. p. W. Stuart-Menteath has forwarded to us 

 a group of pamphlets on the results of his long- 

 continued investigations into the geological structure 

 of the Pyrenees. They have appeared in the Biarritz- 

 A-isociation, and are entitled " Sur les Gisements 

 Metallifferes des Pyr^n^s Occidentales," because the 

 interpretation of that structure greatly depends on the 

 geological age of certain metalliferous (chiefly iron) 

 deposits, in regard to which he differs widely from 

 some members of the French Geological Survey. The 

 question is too long and intricate to be dealt with in 

 a short note, so that it must suffice 

 to say that the map in one of the 

 pamphlets, which represents his own 

 views and recalls certain parts of the 

 Alps, has a very reasonable aspect, 

 and that he is opposed to a school of 

 geologists in France who make 

 greater demands on flat-folding and 

 overthrusting than some who have 

 studied that chain are willing to ad- 

 mit. His criticisms chiefly relate to 

 the Survey map of the Mauleon 

 Pyrenees, which is contradictory to 

 his own observations ; and these, as 

 experience has taught him, are likely 

 to be ignored, and if possible sup- 

 pressed. He taxes its authors with 

 misplacing sedimentary and intru- 

 sive rocks, confusing Cretaceous and 

 Upper Palaeozoic deposits, trans- 

 forming typical Cenomanian and 

 Trias into Silurian and Carbon- 

 iferous, and transferring great slices 

 of sedimentary strata from the 

 southern to the northern side 

 of the chain. If the charges 

 which he brings against MM. 

 Bertrand, Termier, and Carez be accepted, we 

 must suppose that French geology is suffering 

 from the incubus of official infallibility not less 

 seriously than did British geology some five-and-thirty 

 years ago. 



Although in the last seven years there have bee«fc< 

 more than a dozen determinations of the constant* 

 of complete radiation, the results obtained hai 

 differed so widely that it has not been possible to* 

 fix on a definite value. Some of the differences may 

 be accounted for by the radiators or the absorbing: 

 surfaces of the measuring instruments not being pew 

 fectly black, or by the neglect of the absorption of the 

 radiation by the water vapour present in the air. Or 

 it may be due to the form of measuring instrument 

 adopted, and in this connection it is worth noting 

 that when the radiation has been measured by 

 thermometric method, the result has in general been 

 high, while the pyrheliometer has given mean results 

 in fair accord with each other. In Scientific Paper 

 No. 262 of the Bureau of Standards of Washington 

 Mr. W. W. Coblentz reviews the work which i 

 been done by his predecessors and recently by himsen 



J^. E. Dean. 



