76 The Filtration Works for the Improvement of the 



we adopted to render the water drinkable was digging a hole in 

 the sand close to the water and allowing it to filter through the 

 sand. By doing so we got fairly pure water, at all events not 

 dangerously poisonous, or I should not have been here to-night. 



Dr. J. M. MacCormac — We all know water is liable to be 

 contaminated during both storage and distribution. And as 

 regards filters, no matter how perfect in their construction, no 

 person can with certainty say how long a filter will remain abso- 

 lutely efficient. Would it not, therefore, be well for a chemical 

 analysis and also a microscopical examination of the water 

 supplied to our city to be made at short intervals by a competent 

 person, and the result of these examinations to be published 

 by the city press ? The public would thereby gain most valuable 

 information, and the medical faculty would be placed in posses- 

 sion of facts of the utmost importance. I would further mention 

 that the principal diseases resulting from drinking unwholesome 

 water are typhoid fever, cholera, dyspepsia, catarrh of the lungs, 

 ulceration of the throat, scarlet fever, and a disease of the bones, 

 besides certain skin diseases. All this shows the great necessity 

 of having drinking water perfectly pure, and free from not only 

 animal matter but also chemical impurities. As regards filters, 

 I consider the Carbon Filter the most useful when the water 

 can be allowed to filter slowly, and is consumed immediately or 

 soon after filtration ; and that the Spongy Iron Filter retains its 

 efficiency for a long time ; where it is necessary to filter rapidly 

 and to keep the filtered water some time before consumption, 

 this filter is preferable. 



Professor FitzGerald. — As to the question of Mr. Speers 

 regarding the nature of the sand, in Dublin some experiments 

 were carried out by Dr. Adney as to the filtering effect of 

 pumicestone, quite loose, like cinders, over which sewage was 

 run, and, purely by aeration, completely purified. At Antwerp 

 the water has been for some years purified by being put through 

 drums containing small pieces of iron, which are rolled over and 

 over. This produces a sort of extremely muddy water, which, 

 on filtering through an ordinary sand filter, is completely 



