"" MR. E. W. BINNEY ON THE ACTION OF OLD COAL-PIT WATER, ETC. 



nearly similar conditions to the cast iron pipe with a leak in it, 

 surrounded by charcoal, previously mentioned by Dr. Henry, 

 and a strong galvanic current can be easily supposed to have 

 been generated and the iron removed by this cause ; but how 

 the carbon and silica have occupied the place of the iron, I 

 am unable to account for. The waters highly charged with 

 carbonic acid would doubtless take up a large quantity of 

 silica in solution, and as portions of iron were removed, parts 

 of silica might take their places, as it is imagined is the 

 case with fossil woods containing silica. In what manner the 

 carbon was deposited, however, I can give no opinion. 



This is a very interesting subject, and requires much further 

 investigation than T can devote to it. The chief object of this 

 communication was to direct the attention of coal masters to 

 the action of old mine waters upon iron, and to recommend 

 them not to place too much trust on metal tubbing alone ; and 

 also to point out the protection which lime in the shape of 

 mortar affords to iron under the most severe tests, — for the 

 water that could decompose an inch casting in four and a half 

 years, must be taken as an extreme case. After the facts 

 stated in this paper, no proprietor of a colliery ought to omit 

 placing a bed of hydraulic lime inside the metal tubbing of 

 his shafts, when so simple and cheap a precaution will tend 

 not only to save a great amount of property, but, what is of 

 far greater importance, preserve a number of valuable lives. 



