TABLE showing the descriptions of Coal won at the Collieries referred to in Tables A, B, D and E. Iron sheets, wire, or other articles of iron are prepared for the molten zinc bath by being immersed in a weak solution of sulphuric or hydrochloric acid. A sulphate or chloride of iron solution is gradually formed, and as this becomes stronger and the acid weaker, it is less useful for its purpose, and finally it is disposed of as waste. sewers. In the Black Country most of the galvanising works have by some. means or other managed to get connections with the local authorities' The objections to the admission of the waste to the sewers are twofold. First, the acidity of the waste or pickle and its resulting action. on the sewer joints; and second, the superabundance of iron salts or acid in the sewage itself, which requires extra lime at the outfall works for neutralisation. In the case of Wolverhampton, when the population was 80,000 and the sewage flow about 2,000,000 gallons per diem, the amount of lime used for neutralisation was as much as 2000 tons per annum, or about 40 grains per gallon of sewage, instead of the average 15 grains. The 'Pickle,' under certain private Acts, must first be neutralised before the discharge into the sewers, but this is not always done, one case being cited at a prosecution where it contained 2305-6 grains of free hydrochloric acid per gallon, and 3408-3 grains of iron per gallon (as Fe) in solution. The wash waters from both vats and sheets or other articles are distinctly acid, and contain from 50 to 100 grains of iron (as Fe) in solution per gallon. At times there is an attempt to run in together wash waters and partially neutralised or decomposed pickle, and the discharges will contain anything between 200 and 700 grains of iron (as Fe) in solution or even more. The inconvenience at sewage outfall works is not only the extra expense of lime required, but the extra sludge formed is very considerable and is more difficult to dispose of, as its manurial nature bulk for bulk is diminished. If the discharge is into a stream direct the results are disastrous. A coat of red oxide is soon formed on the banks and bed, and all vestige of visible life removed. For the economical recovery of the metal and acid from the solution of iron salt many attempts have been made, though the bulk of the trade neutralisation by lime is still resorted to. Mr T. Parker patented a method of treating sulphuric pickle electrolytically, or, more correctly, of securing a continuous regeneration of the pickling bath. To this end the pickling bath is provided with a chamber separated from it by means of a porous diaphragm in which an iron cathode is placed. In the main pickling vessel is an anode of lead, carbon, or other material not attacked by vitriol. The electrodes are connected with a current at about 2 to 5 volts pressure. In the separated chamber is placed a neutral solution of iron sulphate or waste. pickle, and the pickling |