716 EXPERIMENT STATION EECOED. 



" Early iu 1910 there were 20 companies operating in the hard-rock regions, 

 with a total annual capacity of more than 750,000 tons. 



" In the pebble regions 15 companies were engaged in mining operations, 

 with a capacity of 1,500,000 tons per annum. 



" Owing to various causes the hard-rock industry was at a rather low ebb 

 during 1909 and 1910, many plants being entirely closed down, but the operators 

 expect the situation to improve. 



" The pebble industry, however, has been growing uninterruptedly and prom- 

 ises to continue to increase. 



" The life of the hard-rock phosphate is variously estimated to be from 20 to 

 100 years; the deposits of land-pebble phosphate are considered almost inex- 

 haustible." 



On the alleged refutation of the lime factor theory, II, O. Loew {Lamlw. 

 JahrJ)., 39 {1910), No. 6, pp. 1005-1009). — The author again takes issue with 

 the conclusions of D. Meyer (E. S. R., 24, p. 134), and questions the reliability 

 of his results on the ground that the plants, which were harvested at the 

 blooming stage, should have been allowed to mature, and further that too 

 many plants were grown in each pot to secure normal development. The 

 author restates fully his own conclusions with reference to the lime factor in 

 soils and refers to the work of a number of other investigators which confirms 

 his conclusions. 



Increasing' the yield by fertilizing' with carbon dioxid, P. Wagner (Mitt. 

 Dent. Lanclw. GeseU., 25 {1910), No. 12, pp. 176-119; ahs. in ZentU. Agr. Chcm., 

 39 {1910), No. 11, pp. 126-129). — This is an account of pot exijeriments with 

 potatoes to investigate the theory of Krantz that the growth of plants is in- 

 creased by using fertilizers which produce a large amount of carbon dioxid and 

 heavily charge the air surrounding the plants. 



Comparative tests were made of two of the fertilizing materials proposed by 

 Krantz for this purpose, and of guano, green manure (vetch), and ordinary 

 stable manure, as well as nitrate of soda. The results showed that there was 

 no definite relation between the amount of carbon in the different manures and 

 the yield produced, but that the yields depended upon the amount of easily 

 assimilated nitrogen furnished by the manures. 



Plat experiments with fertilizers, J. H. Stewart and H. Atwood {West 

 Virginia 8ta. Bill. 131, pp. 201-2 'i2, pis. 18). — This bulletin gives the results to 

 date of experiments partly reported upon in previous bulletins of the station 

 (E. S. E.. 19, p. 1019), summarizing the results of the whole investigation from 

 1900 to 1910. 



The succession of crops during this period has been rye, wheat, clover, corn, 

 cowpeas, corn, potatoes, rye, and hay (2 years). The results show that the 

 most deficient fertilizing constituent in this soil is phosphoric acid, and that 

 this must be supplied before either nitrogen or potash can be of any particular 

 value. Next to phosphoric acid, nitrogen is the most deficient constituent ex- 

 cept in case of potatoes, which were more benefited by applications of potash 

 than of nitrogen. The results with lime were inconclusive, there being a re- 

 duction of yield when this material was first applied, but an increase in later 

 years. Corn responded more favorably to stable manure than to commercial 

 fertilizers, while with cowpeas the reverse was true. The great importance of 

 carefully saving and using manure was clearly demonstrated in these experi- 

 ments. It is also shown that when commercial fertilizers alone are used these 

 should contain all three fertilizing constituents, but the proportion of phos- 

 phoric acid should be especially high. 



Inspection and analyses of commercial fertilizers, W. F. Hand et al. 

 {Mississippi 8ta. Circ, 32, pp. 35). — This is the first of a proposed series of 



