UTILIZATION OF SEWAGE. 47 



patches of grass about springs are fiimiliar illustrations. On 

 the IDtli of last April VirchoAv visited the sewage farms of 

 Edinbura". From an eminence could be seen the line of 

 demarcation separating the two hundred and fifty acres from 

 the surrounding territory. The fi-esh green verdure of the 

 farm, where the first cutting of grass had already begun, was 

 in striking contrast to the brown fields outside, with nothing 

 in their appearance to indicate the approach of spring. After 

 two hundred years of irrigation, — water-closets being 

 connected with the drains for the last fifty, — there is no 

 pollution of the soil or diminution of the amount of liquid 

 taken up. There is one acre to about one thousand inhabi- 

 tants. (From Virchow's Archives.) 



J. Bailey Denton estimates the loss by evaporation on 

 irrigated lands in England to be equal to one-half of the 

 entire amount used. There the yearly average humidity is 

 between 80 and 8G. Here it is about 70. In this respect 

 the meteorological conditions are more favorable here than 

 there, for the more remote the point of saturation the greater 

 the capacity of air to take up moisture. 



With water and manure delivered without expense to the 

 farmer, profit ought not to be a matter of question. Five 

 years ago R. W. Peregrine Birch published a little pamph- 

 let bearing the title of " Fifty Instances of Profitable Sewage 

 Utilization," and after a detailed account of as many fiirms, 

 concludes : 



First. That there are upwards of one hundred owners 

 and occupiers of land in Great Britain who use sewage for 

 the sake alone of what they can get out of it by agricultural 

 means. 



Second. That of this number more than sixty are tenant 

 farmers, wdio continue to use it, although they have, an- 

 nually at least, the option of ceasing to do so. 



Third. That of the latter number about five-sixths, and 

 of the total number three-fourths, actually pay money for 

 the use of the sewage, either in the form of out-fall rent, 

 unquestionable increase of land rent, or the price of occas- 

 ional dressings. 



Nearly four thousand acres of sewage land, he says, have 



