12 COMPOSITION OF SOLID AND LIQUID EXCRETA. 



traces in the urine. Horse-urine, however, is an ex- 

 ception with regard to lime, as it contains about 60 

 per cent of the lime consumed in the food. For in- 

 formation on the subject of pig-manure the reader is 

 referred to Appendix, Note V. 1 



Before passing from this part of the subject, it may 

 be desirable to place before our readers the composi- 

 tion of the dung and urine taken together, so that we 

 may be able to form some idea of their relative value, 

 weight for weight. As the nitrogen constitutes by far 

 the nl'ost valuable portion of the manurial ingredients, 

 it will be sufficient if we compare them as to their 

 percentage of this ingredient. 



Wfltpr Nitrno-pn Calculated on 



pUSt. dry pe S r U cett nCe> ****** * 



Sheep . . 67 .91 2.7 Jiirgensen. 



Horse . . 76 .65 2.7 Boussingault. 



Pig ... 82 .61 3.4 Boussingault. 



Cow . . .86 .36 2.6 Boussingault, 



From these figures we see that, in their natural con- 

 dition, the excreta of the sheep are the most valuable ; 

 those of the horse and pig coming next ; while those 

 of the cow are the poorest, containing one-third as 

 much nitrogen as those of the sheep, and one-half as 

 much as those of the horse and pig. This difference, 

 however, is due almost entirely to the different per- 

 centage of water the excreta of the various animals 

 contain in their natural state ; for in the dry state 

 they are seen to contain, with the single exception of 

 the pig, practically the same amount. 



1 See p. 55. 



