178 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY, 



1 plate; 3 figs.).— This bulletin gives a report on fifty varieties of straw- 

 berries, many of them recent introductions. Eleven of these varieties 

 produced flowers without stamens, and therefore needed to have perfect- 

 flowering varieties growing near them to ensure fertilization (p. 72). 



A. P. 



Sugrar Industry of the Island of Negrros. By Austin H. 

 Kirby (West Indian Bull. vol. xi. No. 3, 1911). — The sugar industry 

 was introduced into the island by a religious order in 1849, and increased 

 rapidly with the population until 1893, the year of its greatest develop- 

 ment, when the maximum yield was recorded. Since then the industry 

 has gone back from various causes, and is about 60 per cent, of the 

 maximum at present. Under the old system the annual sugar pro- 

 duction in Negros for the next fifteen years might be about 220,000 

 tons. The adoption of modern methods of manufacture and improved 

 modes of cultivation would probably double the output, and would 

 enable the island to take a very important place in the production of 

 sugar.— -C H, L, 



Sulphur Requirements of Farm Crops in Relation to the 

 Soil and Air Supply. By E. B. Hart and W. H. Peterson (U.S.A. 

 Exp. Stn., Wisconsin, Research Bull. 14, April 1911). — The high sul- 

 phur content of the sheep's fleece (about 2 per cent, of the crude wool) 

 has raised the problem of the relative amounts and forms of this element 

 in feeding materials, and investigations to this end have led to the 

 consideration of the adequacy or otherwise of the natural sources of 

 supply of this element for continuous crop production. 



It is generally recognized to-day by agricultural chemists that the 

 amount of sulphur in plant materials, as determined in the ash, is in 

 most cases too low. A large number of total sulphur determinations 

 have been made on common farm products, and for this work the 

 peroxide method as outlined by Osborne has been used, though the 

 water was not completely boiled off from the hydroxide as directed by 

 that method (p. 2). The results show a much higher content of total 

 sulphur trioxide in plant materials than is found in the ash, rice grain 

 yielding 100 times as much as the ash of that grain, and corn and 

 wheat 40 times as much as the ash of those grains. In oats, cotton- 

 seed, and soy beans, the total sulphur trioxide is about ten times, and 

 in onions and cabbage two to four times, that found in the ash of those 

 materials. The volatile sulphur oils in these products are in part { 

 responsible for the amount of sulphur lost in ignition. In the case of 

 hays and straws the losses are much less, the amount of sulphur 

 trioxide recovered in the ash of mixed hay, for example, being nearly 

 as large as that found in the original material, and in alfalfa and clover 

 hay about 50 per cent. It is evident from this that farm crops in 

 general remove nmch more sulphur from the soil than has been 

 supposed (pp. 3 and 4). 



There are difficulties in the estimation of the total sulphur of soils, 

 most of the determinations hitherto carried out having been made by 



