592 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



Of sewers in brick work, which can be entered and cleansed, we have 

 here about eight and a half per cent of the system; three-fifths are twelve 

 inches diameter, one-fifth fifteen inches, and one-tenth eighteen inches — 

 the aggregate cost being $1,312,242, of which $455,943 is for street basins, 

 man-holes, and other appurtenances. 



In 1855, London had 934 miles of covered sewers, of which 126 miles 

 were pipes. Liverpool, Glasgow, Carlisle, and other Euiopean cities use 

 the combined system, while Manchester, Rugby, Craydon, Edinburgh, and 

 other cities use pipes. In this country, Brooklyn and Chicago are promi- 

 nent examples of the combined sj'stem, and pipes are being adopted at 

 Albany, Hartford, New Haven, Elizabeth, Jersey City, and various other 

 places, in whole or in part. 



The proper materials for trunk mains, in ovals or circles, are brickwork ; 

 stonework, lined and arched with bricks, being preferable for other forma 

 and large sections. Tubes, in Europe, are usually of stone-ware, carefully 

 made from fire-clay; these were imported to this country for the Brooklyn 

 sewers first laid, but have been gradually superseded by pipes of concrete, 

 carefully made with hydraulic cement mortar in iron molds, and on pol- 

 ished cast-iron cores. With material of groat durability, and with great 

 perfection of form and surface, and moderate cost, there is every I'eason to 

 suppose that they will eventually be adopted for general use — about twelve 

 miles of them having been Ikid in Brooklyn since their first introduction, 

 and their operation is a matter of congratulation in the annual reports of 

 the commissioners, in common with the general pipe system. 



The sanitary condition of a populous town in which damp subsoil and 

 foundations, impregnated wells, and contaminated atmosphere are constantly 

 exerting an evil effect on individual health, have therefore, an intimate con- 

 nection with correct systems of sewerage. 



It has been asserted as a matter of theoretical deduction, and of practical 

 illustration in a number of the great cities of the world, subjected to the 

 scourge of destructive epidemics, that the chief ravages of the disease 

 have been confined to certain local districts within their limits', and that 

 these districts are characterised by depressed levels and saturated ground, 

 by improper water supply, and hy defective drainage. 



The victims of the cholera in 1849, at London, were taken in districts. 

 The Health Report of 18 GO says: 



"On dividing the whole of the metropolis into three districts, the highest 

 averaging 63 feet above high water mark, the intermediate 30 feet, and 

 the lowest four feet, we find that the deaths were in the highest, 1 in 346- 

 in the intermediate, 1 in 256, and in the lowest 1 in 93. 



This report abounds in illustrations of effects from damp foundations, 

 impure water, and vast deposits in cess-pools and sewers of sewage matter 

 in fermentation, exhaling carburetted and sulphuretted hj'drogen gas, and 

 other deadly atmospheric mixtures. It was remarked by Pr. Grey, of Lon- 

 don, in reference to the consequences of imperfect sewer action, that 

 "knowing where the greatest mortality L-om typhus, typhoid fever, diar- 

 rhcBa and cholera exist, he could map out accurately, the courses of the 

 great sewers." 



The Registrar General of London, in 1847, refers to the "disease-mist" 



