76 REPORT— 1869. 



inadverteutly both steam and fire were left acting after tlie higher temperature was 

 obtained, the temperature continued notwithstanding. Again, when the fire was 

 in a condition, through neglect, in which it was obviously of no use, the author was 

 still astonished to find that, as the apparent result of the steam alone, the tempera- 

 ture was at a satisfactory point. This last observation led the author to test the 

 matter in the laboratory in the following manner. Being convinced that the high 

 boiling-point of his liquors had something to do with the phenomenon, he selected 

 a solution of a salt (nitrate of soda) ha\-iDg a high boiling-point, about 250° F. 

 (121°'l C). The nitrate of soda was placed in a vessel surroimded by a jacket, 

 steam was let into the intervening space imtil a temperature of nearly 212° F. 

 (100° C.) was obtained ; the steam was then shut off and an open pipe immersed 

 in the solution. Steam from the same source was thrown directly into the liquor ; 

 in a few seconds the thermometer slowly but steadily moved, and minute after 

 minute progressed until it touched 250° F. (121°-1 C). This thoroughly ex- 

 plained the results obtained in the digesting vessel, and became to the author of 

 immense practical value. He discarded the use of fire applied to his vessels, 

 which had not only been tedious and troublesome in operation, but involved a 

 loss of many hundreds of pounds per annum in destruction of apparatus, and used 

 only steam as a vehicle of heat. As a corroboration of the theory which seems to 

 explain the apparent paradox, the author finds that the temperatures of his solu- 

 tions are in the exact ratios of their specific gravities, and have no connexion 

 with the temperature of the steam, which never exceeds 212° F. (100°C.): the 

 greater the specific gravity of an acid solution the higher the boiling-point, and 

 therefore, whatever the boiling-point of the solution in water of any sfilt, to that 

 point, or nearly, will steam of 212° F. (100° C.) raise it. 



A Chemical Method of treating the Excreta of Towns. 

 By Edw. C. C. StaJifoed, F.C.S. 



In this paper the author advances arguments to'^show that the present water- 

 closet system cannot be a permanent one, and submits a rational method by which, 

 using charcoal instead of earth, the drv' sj-stem can be universally employed in 

 cities. The specified objections to the use of water are : — 



1. The enormous cost of the works required in proportion to the small amount 

 of noxious material to be removed. 



2. The large annual outlay required to keep the closets in order, and their unfit- 

 ness for the dwellings of the poor. 



3. The immense quantity of water required (365 times the weight of the excreta) 

 where, as in many towns, there is much difficulty in obtaining it. 



4. It results in a subterraneau flood of filthy water, which must flow somewhere, 

 and wherever it flows it pollutes the region, thus disseminating and distributing 

 the evil. 



5. The material removed has its value of 30.<. per ton reduced by dilution to 

 \d. per ton, which it is impossible by any known chemical method to extract with 

 profit. 



G. The sewers generate an abundance of noxious gases, which difTuse malaria 

 into our streets and dwellings. 



Instances are given of large outbreaks of gastric and other fevers entirely trace- 

 able to this source ; and authorities are quoted to show the extreme danger of these 

 poisonous emanations. Dr. Fergus, of Glasgow, first pointed out a fruitful cause of 

 escape of these gases into dwelling-houses. He frequently noticed a peculiarly 

 offensive sickly odour in attending patients suffering from gastric fever, and in all 

 casts traced it to the lead siphon and soil-pipes of the water-closet. On examina- 

 tion, these were always found to be perforated with small holes, through which 

 the gases freely escaped into the house. In some cases the whole interior of the 

 pipe is eaten away, and lined with a light-brown powder, the nature of which was 

 investigated by the author of this paper. From the several sr alyses given, it con- 

 tains 8(3 to 92 per cent, carbonate of lead and 2 to 3 per cent, carbonate of lime. 

 The carbonic acid, aided by the other gases of decomposition, act on the lead, pro- 

 ducing carlonate of lead under similar* conditions which obtain in its manufactuie 



