410 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



consists in simply touching the extremity of the stigma of 

 the flower about to bloom with a brush dipped in honey, or, 

 still better, in honey mixed with the pollen of the plant to 

 be operated upon. This, in the case of Hibiscus Mexiccmus, 

 which had never borne fruit, resulted in the production of 

 perfect seeds. The operation has succeeded very well with 

 certain fruit-trees, some of which have thus been caused to 

 produce fruit for the first time. As an explanation of this 

 result, it is suggested that the honey keeps the grains of pol- 

 len upon the stigma, and thus favors the development of the 

 pollen tube, which is indispensable to fertilization. The sub- 

 stitution of glycerine for honey in the experiment has been 

 suggested. 3 D, December 25, 1873, 715. 



CONTINUED GROWTH OF BARLEY ON THE SAME LAND. 



As the result of experiments on the growth of barley on 

 the same land for twenty years in succession, Messrs. Lawes 

 & Gilbert report that when the same crop is grown consecu- 

 tively on the same ground for a series of years, mineral ma- 

 nures, alone, fail to enable the plant to obtain sufficient nitro- 

 gen and carbon to yield even a fair crop ; that nitrogenous 

 manures, alone, increase it very considerably ; but that the 

 largest crops are obtained when nitrogen and mineral ma- 

 nures are applied together. In the case of barley, these com- 

 bined manures gave for twenty years in succession, on the 

 same land, rather more of both corn and straw than farm- 

 yard manure did, considerably more than the average bar- 

 ley crop of the country grown under a system of rotation of 

 crops, and an average weight per bushel of between fifty- 

 three and fifty-four pounds. 13 A, February 14, 1874, 179. 



MANUFACTURE OF MAT-WORK FROM THE BARK OF THE 



LINDEN. 



A great variety of articles, including grain-bags, wagon- 

 covers, floor-covers, ropes, sails, etc., is made in Russia from 

 the inner bark of the bass-wood or linden-tree ; a million of 

 trees being destroyed annually in the manufacture, and the 

 value of the articles produced amounting to about $2,400,000. 

 The bark is collected by the peasants in May and June, when 

 the ascent of the sap renders peeling easy. That of the low- 

 er part of the trunk, generally employed for roofing, is ob- 



