ON THE POLLUTION OF THE RIVER IRWELL. 245 



XV. The pollution of the River Irwell and its Tributaries. 

 By Charles A. Burghardt_, Ph.D. 



Read February 23rd, 18 86. 



[Plates X., XI., XIT., & XIII.] 



I HAVE thouglit it would be interesting to the Members 

 of this Society perhaps^ if I laid before them the results 

 of many analyses of the water of the Biver Irwell extending 

 over a period of two years^ and also analyses of some of the 

 most important tributaries of the Irwell above Manchester, 

 including at the same time the Irk and the Medlock within 

 the boundary of Manchester. There have been several 

 investigations already into the condition of the Irwell &c., 

 the first being that of Lyon Playfair, in 1844. Undoubtedly 

 at that time the river was extremely filthy, but I am quite 

 certain from my own investigations that it was inaccurate 

 to state that large quantities of sulphuretted hydrogen, 

 phosphoretted hydrogen, and other dangerous gases were 

 evolved from the waters. Most certainly it could never 

 have evolved phosphoretted hydrogen, because this gas can 

 only be prepared by the reduction of phosphates under 

 difficult chemical circumstances, which could not obtain in 

 a river, but assuming for the sake of argument that this gas 

 did succeed in forming after immense efi'ort, and arrived in 

 the shape of a bubble at the surface, if it consisted of the 

 very inflammable modification, it would immediately take 

 fire in the air, and burn at once to phosj)horus pentoxide, 

 and this latter body being one of the most hydroscopic 

 bodies known to the chemist, would immediately vanish 

 into the river again, now in the form of phosphoric acid. 

 After this it might recombine with calcium or magnesium, 

 and await a second metamorphosis. Regarding the sul- 

 phuretted hydrogen at the period of Lyon Playfair's investi- 



