260 



Station in 1889, an increase of 20 per cent is shown in the finest grade 

 and a decrease of 30 per cent in the coarsest grade, as compared with 

 the bones annhzed in the four preceding years. The average selling 

 price of twenty-four brands represented is $34.40 per ton; the aver- 

 age Station valuation is $35.55. The nitrogen of the complete fer- 

 tilizers analyzed at the Station is derived chiefly from organic matter. 

 Considering it to have come from materials as good as the finest 

 form of bone, it is found to have cost 50 per cent more than the 

 average cost of nitrogen in the finest bone. The average cost, for 

 the year, of available phosphoric acid in complete fertilizers, which 

 includes both the soluble <ind the reverted, is given as 9.9 cents per 

 pound. The phosphoric acid in the finest bones — over 45 per cent of 

 the samples analyzed — cost only 6.8 cents per pound. 



The analyses of miscellaneous samples, consisting of dissolved 

 bones, dried fish, superphosphates with potash, and plain superphos- 

 phates, showed that those brands in the hands of dealers are fine and 

 dry and furnish nitrogen, ])hosphoric acid, and potash much cheaper 

 than the aA'erage mixed or complete fertilizer. 



Fish guanos show a high commercial valuation, and their guaran- 

 tees, as a rule, were found to be kept. A sample of " phosphate 

 meal," or " Peine-Thomas Scoria," sold at $25 per ton, contained 

 5.45 per cent available and 14.89 per cent insoluble phosphoric acid. 

 In Germany, this material has been found to be a valuable source of 

 phosphoric acid, and because of its low cost is widely used. The use 

 of that produced here must depend largely upon its cost and the value 

 of the phosphoric acid it contains. 



BULLETIN No. (51, OCTOBER 31, 1889. 



Experiments with different breeds of dairy cowSj M. E. Gates, 

 Ph. 1). (pp. 3-11). — This is a report for August, September, and 

 October, 1889, of the experiments explained in Bulletin No. 57 of 

 this Station. In addition to the descriptions of the animals and 

 records of food and product, tables are given '• showing percentages 

 of total solids contained in the milk of individual cow^s and in the 

 mixed milk of herds for the months of August and September. The 

 chief object in the limited chemical examinations was to secure data 

 relative to the variations in quality of the milk from individual cow^s 

 of the same breed." These variations were not marked, but seemed 

 to be influenced by changes in atmospheric conditions and quality of 

 green food supplied as affected by the extreme moisture of the season. 

 BULLETIN No. 62. NOVEMBER 6, 1889. 



The horn fly (IEe.^iatobia serrata), J. B. Smith (pp. 3-40). — 

 This contains an accoujit of the author's observations on this insect, 

 first noticed in this country in 1887, and a review of an extensive cor- 

 respondence on the same subject. The life history and anatomy of 

 the insect and its difi^erent stages are described in detail, and various 



