December, 1912.1 



451 



The crop is ready to dig when the roots are mature, which can be 

 ascertained by cutting a few roots. If, on drying, the wound heals over 

 with a whitish starchy appearance, the roots are ripe ; if they turn black- 

 ish in colour, they are not. Digging may be done in the field by means 

 of a ridge plough, after the vines have been cut. Any unsound and 

 bruised root will decay and should not be stored. After the roots have 

 sweated a little they can be packed in ventilated cases for marketing. 



LAND AND WATER ON THE EARTH'S SURFACE. 



The publication two years ago, by A. Baldit, of the results of a new 

 measurement of the land and water areas on the surface of the globe, has 

 suggested to Dr. H. Wagner a comparison, says the Geographical Journal, 

 of the new results with those previously given. 



As regards the whole surface between 80°N, and 60°S. the percentages 

 obtained by Wagner, Krnmmel and Baldit vary inappreciably, Wagner 

 showing 28'5 per cent, of laud, the other two 28*4 per cent. The total land 

 area within those latitudes is given by Baldit, however, as 550,000 square 

 kilometres less than Wagner's figures. With the necessary corrections 

 to Baldit's estimate for the extreme north and south, the results for the 

 whole surface of the globe appear as follows : Land 149,000,000 sq. kilom. 

 (57,500,000 sq. miles) ; water 361,000,000 sq. kilom. (139,400,000 sq. miles) or 

 29*22 and 70 88 per cent, respectively. This gives the proportion of land 

 to water as 1: 2*42. 



DESTRUCTION OF LANTANA. 



This plant is apt to become a great nuisance in tropical countries on 

 cultivated and pasture land, owing to its dense growth and extraordinary 

 vitality. It appears from the Journale d ' Agriculture Tropicale (1912, 

 12, 154) that an attempt is now being made in New Caledonia to combat the 

 pest by introducing a species of fly of the Agromyzidte family from 

 Hawaii. The insects have been distributed in the environs of Numea on 

 land infested with Lantana. As a result the larvte of the fly have been 

 found in many of the seeds and it is intended to extend its distribution in 

 the colony. The result of the experiment will be watched with interest; 

 it must be borne in mind, however, that where a new animal species has 

 been introduced to destroy some pest it has itself sometimes proved to be 

 injurious in other directions. — Imperial Institute Bulletin. 



BENGAL RICE. 



The yield of rice per acre in Bengal is estimated (Spice Mill, 1912, 35, 

 526) at about 800 lb. of autumn to 1,200 lb, winter rice ; in Eastern Bengal 

 and Assam from less than 700 lb. of autumn-sown to slightly more than 

 1,100 lb. of spring or summer-sown ; in Madras the yield varies from P00 lb. 

 grown on non-irrigated to 1,100 lb. on irrigated fields ; in Lower Burma 

 which has very little irrigation the yield is 1,176 lb. on non-irrigated soil, 

 —Imperial Institute Bulletin. 



