1873O A Solution of the Sewage Problem. 67 



it not that the tasters know whence it comes they would not 

 notice it. On standing, the water acquires no disagreeable 

 odour; it forms no deposit, nor does it give rise to " sewage 

 fungus " or other vegetable growth along the water-courses. 

 Fish will live in it, — not only hardy varieties, but the more 

 delicate kinds, such as gudgeon, to which a very slight taint 

 of impurity is fatal. When the inquirer further finds that 

 the effluent water is not too hard to interfere with its domestic 

 use for washing or cooking purposes, he will endorse the 

 opinion which the writer has deliberately formed, that there 

 are not many English rivers on which large towns are situated 

 which are as free from real impurity as the effluent water 

 from sewage purified by this process. 



Instead of fixing upon a fanciful standard of purity 

 which could never be attained in practice, common sense 

 decides that an effluent water from sewage is fit to be 

 discharged into a running stream if it contain a less per- 

 centage of impurity than the water of that stream : the 

 word " impurity " being not strained beyond its legitimate 

 meaning, or made to include perfectly harmless constituents. 



Let us now pass to the next point of inquiry — the manurial 

 value of the "native guano," and the cost at which it is 

 produced. 



Of the value of a manure, chemistry can tell us little more 

 than it can of the value of water. Just as mere chemical 

 analysis would utterly condemn water containing Liebig's 

 extract, infusion of tea, or a glass of bitter ale, as largely con- 

 taminated with nitrogenous organic matter or albumenoid 

 ammonia ; so chemistry, by taking a fictitious standard for 

 manures, and judging only by the percentage of two of the 

 many necessary constituents of the food of plants, gives 

 an arbitrary money value to a manure, which is often 

 exceeded by the price it fetches in the market. Agri- 

 culturists frequently pay more for nitrogenous and phosphatic 

 manures than the price assigned to them by chemical analy- 

 sis, and the sales of " native guano " form no exception to 

 this rule. 



In the autumn of last year the writer satisfied himself as 

 to the alleged agricultural value of the manure, by personal 

 enquiry amongst the farmers who had used it. With scarcely 

 an exception, the farmers (of whom he saw twenty or thirty) 

 were unanimous in their approval of " native guano :" many 

 of them were shrewd, intelligent men, well acquainted with 

 the various artificial manures in the market ; they had tried 

 " native guano " with intelligence on different fields against 

 other manures, and were assured that — putting equal values 



