200 3Iode of extracting Manure from Sewage Water. 



and calcareous salts which it holds in solution would render it 

 admirably adapted for this purpose ; far more so than common 

 spring or river water, as it contains a much larger proportion of 

 fertilizing ingredients. The manure prepared by the above- 

 described process, as I need hardly point out to you, would be 

 apt to vary considerably in composition at different times, and 

 under different circumstances, particularly if the manufacturer 

 were not careful in apportioning the lime to the sewage matters ; 

 but when properly made, of course it ought never to be less rich 

 than the specimen analysed. 



We want experience before we can decide as to the exact value 

 of this fertilizer. But few experimental trials have been made 

 with it, and consequently its powers have not as yet been fully 

 proved. I have been informed, however, that wherever it has 

 been used, it has furnished very satisfactory results, particularly 

 when applied to wheat crops, and used in conjunction with some 

 alkaline manure. j remain, Sir, 



Yours respectfully, 



Thornton J. Herapath. 



Mansion House, Old Park, Bristol, 

 April lOtk, 1852. 



Numerous plans have been lately suggested for the application 

 of town-sewage to agriculture, but without, I believe, any decided 

 success. Many towns, too, I understand, are just completing 

 new sewage arrangements, and are at a loss how to apply the 

 contents delivered at the new outfall. It is, therefore, doubly 

 important that a gentleman of Mr. Herapath's authority on che- 

 mical subjects has made us acquainted with a plan tested by 

 some years' experience. The manure so prepared, which he was 

 so good as to send me, is absolutely inodorous. — Ph. Pusey. 



XL — On the Use of Nitrate of Soda as a Top-dressing for Wheat, 

 at Holkham. By H. W. Keary. 



To Philip Pusey, Esq, 

 Dear Sir, — I am sorry I have not been able sooner to send you 

 the enclosed results of my experiments with nitrate of soda and 

 salt, as a top-dressing for wheat. I think you asked for a short 

 explanation as to the mode and time of application. I believe 

 the safest rule for commencing is, to do so when the wheat first 

 makes a start in early spring, and as this does not of course 

 always occur at the same time every year, but depends entirely 

 upon the season, no fixed rule as to time can be laid down. I 

 have generally begun to top-dress about the middle of March, 



