576 



NATURE 



[December 30, 1920 



(vol. viii.) further material has accumulated, rendering 

 a revision of the genus necessary. 



The status of the rook in its relation to the farmer, 

 fruit-grower, and forester is briefly reviewed by Dr. 

 W. E. Collinge in the Journal of the Ministry of 

 Agriculture for December. Dr. Collinge is of opinion 

 that this bird has become too numerous, and, as a 

 consequence of the stress of competition, it has taken 

 to feeding upon cultivated crops. He contends that 

 if repressive measures were put into force and care- 

 fully carried out the rook would soon assume its 

 normal place again, and prove to be one of the 

 most useful birds to the farmer in helping to con- 

 trol the larvae of such injurious insects as click- 

 beetles and crane-flies. The rook to-day, the author 

 estimates, consumes about 80 tons of cereals,' 32 tons 

 of potatoes and roots, 7J tons of insects beneficial to 

 the farmer, and 65 tons of injurious insects, slugs, 

 snails, etc. This last item is significant, and sug- 

 gests an extension of this analysis directed to show 

 approximately how many tons of cereals, potatoes, 

 and roots would have been consumed by the 65 tons 

 of injurious insects and their offspring if they had 

 not fallen a prey to the rook. 



In No. 15 of the Economic Proceedings of the 

 Royal Dublin Society (November, 1920) Prof. G. H. 

 Carpenter reports on the injurious insects and other 

 animals observed in Ireland during the years 1916-18. 

 Among the various pests mentioned are larvse of a 

 species of Bibionid fly which caused much damage in 

 wheat-fields by feeding on the roots, and those of 

 Bibio Marci, L., found attacking potatoes stored in 

 a pit. The flax flea-beetle (Longitarsus parvulus, F.) 

 caused serious injury to the flax crop during the three 

 years under review, and it was found necessary to re- 

 sow the crop in several localities, no method of 

 control being referred to. Storehouse beetles (Ptinus 

 fur, L., and P. tectus, Boield.) are recorded as 

 devouring very varied substances. Those of the first- 

 mentioned species are believed to have been intro- 

 duced from Tasmania, and were noted in 1908 in a 

 consignment of almonds, and in 191 1 from stuffed 

 birds. Early in 1918 P. fur was received from Dublin 

 localities among seeds of henbane intended for sow- 

 ing, while P. tectus was discovered in a chemist's 

 store of casein. The report is adequately illustrated, 

 but shorter than many of its predecessors, which is 

 possibly accounted for by the war and by conditions in 

 Ireland generally. 



The first Report of the National Institute of Agri- 

 cultural Botany, recently issued, shows that en- 

 couraging progress is being made with the new 

 scheme. The aim and policy of the institute are to 

 develop new and reselected varieties of all kinds of 

 farm crops and to " grow on " promising types until 

 sufficient stocks are available for distribution through 

 the seed trade to the farmer. Liberal financial assist- 

 ance has been forthcoming, not only from private 

 benefactors, but also from the seed trade and farming 

 industry. As the official seed-testing station is to be 

 incorporated with the institute, a building grant and 

 loan were obtained from the Development Commis- 

 NO. 2670, VOL. 106] 



sion.. It is now hoped to gain new subscribers to 

 build an adequate maintenance fund. The head- 

 quarters of the institute, now rapidly approaching 

 completion, are being erected at Cambridge, and 

 include housing accommodation for a portion of the 

 staff. The rest of the 36 acres of this site is avail- 

 able for trial grounds. In addition, the Hiam 

 Farm at St. Ives (Huntingdonshire) (354 acres) 

 will be used as a seed multiplication farm, and 

 39 acres of rich market-garden land at Orms- 

 kirk, Lancashire, are being developed as the 

 potato testing station. Mr. Wilfred H. Parker has 

 been appointed director of the National Institute, 

 but the Seed Testing Station will retain its independ- 

 ence under its own director, and will be equipped to 

 test all kinds of agricultural, garden, or forest seeds. 

 It is hoped that the buildings will be ready for 

 occupation by August, 192 1, and arrangements are 

 being made whereby the work of the institute will be 

 carried on with the least possible delay. 



The possibility of a general w-orld-wide sinking of 

 sea-level to the extent of nearly 20 ft. during post- 

 Glacial times is discussed by Prof. R. A. Daly in the 

 Proceedings of the National .-\cademy of Sciences 

 (Washington) (vol. vi.. No. 5), and at greater length in 

 the Geological Magazine (vol. Ivii., No. 672). Observa-" 

 tions on coast-lines in many parts of the world show 

 approximately this degree of emergence, and the facts 

 appear to warrant belief in synchrony in the age of 

 the strands. Prof. Daly, however, points out that 

 the suggestion is published, not to express a fixed con- 

 clusion, but to invite criticism and to test the idea 

 in different parts of the world. If this emergence is 

 established throughout the world, its explanation 

 cannot be found in a change in the earth's centre of 

 gravity or in a change in its speed of rotation. Prof. 

 Daly suggests, an increase in the past in the volume 

 of existing ice-caps as a possible explanation. He 

 calculates that a thickening of the Antarctic ice-cap 

 to the average amount of 700 ft. would lower the sea- 

 level by about 20 ft. by the abstraction of water from 

 the ocean basins. 



A REPORT on two- pilot-balloon ascents made at 

 Shoeburyness by Mr. N. K. Johnson is published by 

 the Meteorological Office as Professional Notes 

 No. 13. Both ascents were made on February 18 

 last. It is claimed that the results indicate the 

 limitations and uncertainty of the single-theodolite 

 method of observation, while they show the accuracy 

 obtainable in determining upper-wind velocities and 

 directions by the double-theodolite method. The first 

 ascent was observed for 74 minutes, and in 48 minutes 

 had attained 26,400 ft. The balloon then apparently 

 developed a leak, and sank continuously to 12,800 ft., 

 when it was lost in a light bank of haze. The 

 second ascent w-as started at 11.50 a.m., 85 minutes 

 after the first ascent, and was followed for 116; 

 minutes. The balloon rose to 32,000 ft. in 64 minutes, 

 which is said to be in excellent agreement with the 

 rate of ascent given by Dines's formula. It after- 

 wards maintained a practically uniform height untit 

 the 93rd minute, and afterwards fell slowly to- 

 27,000 ft., when it was lost to view-. Both balloons 



