+-------------+-----+-----------------+--------+-------+-------+-------+------+ | | | B | | | | | | |Description | A +--------+--------+ E | F | G | H | I | | | | C | D | | | | | | +-------------+-----+--------+--------+--------+-------+-------+-------+------+ |Midden Towns 57·68| 12·467 | 14·910 | 85·057 | 2·926 | 3·804 | 4·515 | 8·078| | | | | | | | | | |Water-Closet | | | | | | | | |Towns 50·54| 16·936 | 14·357 | 81·823 | 3·287 | 4·692 | 5·410 | 7·462| +-------------------+--------+--------+--------+-------+-------+-------+------+ We shall all of us be ready to grant that the addition of excremental matters must be something _extra_ added to the sewage, and that such extra matter must be either in suspension or solution. The fact, therefore, that the total solid and suspended matters is less by 3½ grains in the water-closet towns than in the midden towns can only be accounted for by the enormous dilutions of the excremental matters in the sewage. Notwithstanding this dilution we find that the water-closet town sewage contains 20 per cent. more combined nitrogen than midden town sewage, 23 per cent. more ammonia, and, what is very remarkable, 35 per cent. more suspended mineral matter. This excess of mineral matter in suspension could only be caused by the precipitation of mineral matters by the ammonia and sulphuretted hydrogen formed by decomposition of the albuminous and other organic matter. This excess of mineral matter in suspension must therefore be taken as a measure of the enormously increased putrefaction in water-closet sewage, a putrefaction probably to a great extent brought about by the millions of microbes which are provided from the human intestines with the excrement, and we must therefore assume that the increase of mineral matter in suspension is an indication that a large quantity of foul putrefactive gases has been given off into the streets and houses of water-closet towns. This table, therefore, seems to me to conclusively demonstrate that the sewage of water-closet towns is far more bulky and far more filthy and dangerous than the sewage of midden towns. Sewage is not to be regarded too absolutely from its chemical side. We must use our senses, inclusive of our common sense, in coming to a conclusion, and we must not pin our faith on analyses alone. When I am told that it is of little use to deal with solid excreta, because the liquid household slops alone are as foul and difficult to treat as the complete mixture, I confess I am incredulous.