958 TliAKSACTIONS OF THE AMERICAN INSTITUTE. 



Mo., the erection of live filtering reservoirs, eiacli 2G0 by 156 feet^ 

 leaving one out of use for the purpose of removing its accumulated 

 sediment. The filter-beds are to be formed as follows, commencing 

 from the puddle bottom : Drain pipe, twelve inches in depth ; broken 

 stone, twent^'-four inches in depth ; gravel of nut size, twelve inches ; 

 gravel of pea size, twelve inches; coarse sand, twelve inches; fine 

 sand, eighteen inches. About seventy-five imperial gallons of water 

 per day will be filtered through each square foot of surface, and as the 

 area of each filter is 37,440 square feet, it will yield 3,360,847 U. S. 

 gallons in twenty-four hours. As the city will require about 

 12,000,000 U. S. gallons daily, the five such filters will be amply 

 sufficient." 



In relation to this item, Mr. C. E. Emery said that the water of 

 •western rivers is not very inviting for drinking purposes, as it very 

 much resembles that taken from a mud puddle. It is, however, 

 drank without injurious eff'ects. At the mouth of the Mississippi 

 river the fresh water floats on the surface of the salt waters of the 

 gulf, and it is not unusual there to be able to drink the nmddy 

 water lifted by a pump from near the surface, while the water admit- 

 ted at the sea-cocks in the ship's hold is clear salt sea water. 



Dr. L. Bradley remarked that this muddy water is found in all 

 parts of the Missouri river. . There are certain localities which 

 furnish this peculiar mud. It is not unhealthy ; the water is drank 

 right from the river without any filtering. It seemed to him, how- 

 ever, that it would be cheaper to bring down the Mississippi water 

 for this purpose. The Missouri river water always gives persons 

 who are not use to it the diarrhea, though it is not unpleasant to 

 take. 



The regular subject for the evening was announced to be 



Steam Engines. 



Mr. J. B. Eoot said he would inquire why it is that nine-tenths of 

 the power of an engine is lost. An accurate table of the loss by 

 friction in engines is much required. Nothing reliable on this point 

 has yet been had. Where the friction of an engine is great, the steam 

 has to be increased in proportion, so if we could reduce this friction, 

 say even one per cent, we would have less pressure to raise, and thus 

 gain to that amount. He also thought that important savings would 

 be made by improvements in the boilers where the steam is generated. 



Mr. Charles E, Emery was called upon to speak by several mera- 



