Water Supply of Belfast. 77 



purified. Bacteriological experiments show conclusively a very 

 marked eflfect of iron in freeing the water from micro-organisms, 

 whether by actual destruction of the microbes, or by causing 

 them to be entrapped in the muddy precipitate and filtered out 

 along with it. 



Mr. Macassey said in reply — I must trouble you again for a 

 few minutes. I am sorry my friend Dr. Letts has left the room. 

 I should have liked him to be here while I make a few observa- 

 tions in reply to his statement. There is no doubt that a few 

 years ago there was a controversy in the newspapers — some of 

 you may remember it — in which the principal writers were the 

 learned professor and myself. You can quite understand the 

 difficult position in which I was placed. I was purely an engineer, 

 and knew nothing about chemistry. However, I adopted a safe 

 course, I advanced nothing, but I dealt with the matter as the 

 German critics deal with our venerable old Bible, I went on 

 external evidence, and the professor was the first person to drop 

 the controversy. It is no doubt surprising to hear the difference 

 of opinion among chemists as to the water in general. Some 

 describe the water as most excellent for all purposes, while 

 others tell us it is impure and dangerous. I think you will 

 come to the conclusion that the Belfast water is really not so bad 

 as it is stated to be, but we had better spend a little money and 

 make the thing all right. An eminent chemist, Professor Tidy, 

 of London, after a complete and careful examination, told the 

 Commissioners that the water as furnished by them was a 

 wholesome water, and would not be likely to produce disease. 

 Mr. Greenhill has mentioned domestic filters. I had intended 

 dealing with these but found that the subject would make a 

 very good paper in itself. At some future time I shall be much 

 pleased to bring this subject before the Society. With regard 

 to the sand to be used for the purposes of filtration in connection 

 with these works, we use both sea and Lough Neagh sand. Will 

 that sand be effective ? In my opinion it will. In the early 

 experiments to test the efficiency of sand Professor Frankland 

 did use the ferruginous sand, but in the latter experiments as 



