1898.] PUBLIC DOCUMENT — No. 33. 119 



their analyses have already been published in three bulletins, 

 Nos. 45, 48 and 49, March, July and November, 1897, a brief 

 statement of the names of the difterent articles analyzed will, 

 on this occasion, suffice to convey some idea of the extent 

 and the character of the work accomplished. Only a few of 

 these materials of more special importance are reserved for a 

 subsequent short discussion. 



The substances tested from Dec. 1, 1897, to Dec. 1, 1898, 

 are as follows : wood ashes, 89 ; cotton-seed meal, 23 ; cot- 

 ton-seed hull ashes, 3 ; cotton factory waste, 5 ; tankage, 

 bone and fish, 17 ; muck, peat and soils, 16 ; chemicals, 14 ; 

 acid phosphates and dissolved bone-blacks, 5 ; natural phos- 

 phates, 6 ; tobacco refuse, 2 ; complete fertilizers, 31 ; mis- 

 cellaneous, 9 ; Damara land guano, garbage cremation ashes 

 and wool washings, each 1. 



Aside from this work are the complete analyses of 36 

 samples of tobacco leaves, together with numerous tests 

 for the quality of ash and rate of combustion. See Bul- 

 letin No. 47, on tobacco experiments, published in April, 

 1897. 



The responsibility of the genuineness of all articles sent 

 on for examination rests with the parties asking for the 

 analysis. Our publications of the results refer merely to 

 the locality they come from, to avoid misunderstandings. 

 Samples of fertilizers collected from original packages by 

 authorized agents of the station in the general markets fur- 

 nish the material for official analyses, and are considered 

 genuine articles. 



2. Notes on Barn-yard Manure. 



The importance of l)arn-yard manure as a home source of 

 plant food cannot be over-estimated in a mixed farm man- 

 agement. In a well-regulated rational system of stock feed- 

 ing it is one of the cheapest if not the cheapest source of 

 valuable manurial constituents. An exceptional liability to 

 vary in composition is the strongest objection which can be 

 raised against its exclusive use as a manure supply for the 

 farm and garden, yet this objection has lost much of its force 

 since the causes of variation are better understood, and may 

 thus be avoided to a considerable extent. We have learned 



