Oct. 10, 1884.] 



♦ KNOWLEDGE ♦ 



295 



its hardness, and cleansed of all its other impurities, passes 

 on to the supply pipes. 



The reagent used has been patented under the specific 

 name of " Maignen'a Anti-Calcaire." It consists of an 

 admixture of lime, soda, and alum in proportions suitable 

 to the requirements of each case. The inventor claims, 

 with perfect j ustice, that when this powder is made to act 

 upon hard water, it not only precipitates the carbonates, 

 thereby correcting the temporary hardness, but also eliiui- 

 nates the sulphates, and thus gets rid of the permanent 

 hardness. In passing through the indestructible asbestos 

 filter, on to which the precipitated materials settle in such 



Fig. 33. 



■a way as to form a more jierfect strainer, the water is ad- 

 mirably fitted for the use of manufacturers and engineers. 

 A small portion of the carho calcis added to the filter frame 

 vvill deprive the filtrate of every other impurity, and render 

 the supply a good potable water. We find that the "Anti- 

 Oalcaire," supplemented by the Filtre Rapide, is quite 

 adequate to the production of a supply of the highest 

 value to both the householder and manufacturer. 



^^rz* 



MAICNENS 



(REClSTEflEO) 



IjIWATER SOFTEt>llNpJ 



PAN 



Fig. 34. 



FiL'. 35. 



The next matter of importance is one of commercial sig- 

 nificance — viz , its price. It is stated* that one pound of 

 " Anti-Calcaire " powder suffices to soften from 300 to 500 

 gallons of water, that pound being retailed for the sum 



* "Water, Preventable Disease and Filtration." By P. A. 

 Miignen, 22 and 23, Great Tower-street, Loudon, E.G., 1884. p. 30. 



of 6d. It may also be interesting to know how it can be 

 turned to account in the economy of an ordinary home ; 

 we therefore quote the following extracts for the benefit of 

 our readers : — 



" M. Alexis Soyer says that the quantity of tea which gives three 

 cups with hard water will make five cups with soft water; so that 

 a family which consumes 1 lb. of tea per week, say at 33. per lb., 

 would spend £7. IGs. per annum with hard water, whilst with soft 

 water they would only require 32 lb., at 3s. per lb. — cost, £4. 16s. 

 Thus the chalk present in the London water costs a family of five 

 persons a loss of £3 a year in tea alone. To remove this chalk by 

 our new system of softening water would only cost 3d." 



" To soften 100 gallons London water with washing-powders and 

 so.ip, the cost would be, say, washing-powders 5d., and soap (2i lb. 

 at 4d.) lOd. — total, Is. 3d. To soften the same quantity by oar 

 precess would cost about 2d." 



"The boilers, which would last ten years with soft water, are 

 often worn oat in two years with hard water; so that in the former 

 case it is sufficient to deduct 10 per cent, for depreciation every 

 year. In the latter, upwards of 50 per cent, must be deducted, to 

 say nothing of the stopping of engines and loss of time. Hard 

 water takes 8i minutes to boil, whilst soft water boils in 

 6 minutes." * 



Fig. 3.5 shows a convenient form of water-softening pan 

 which is suited to the wants of a household. Into this 

 small reservoir the " Anti-Calcaire " may be introduced, 

 either automatically or by being merely thrown in. If the 

 latter operation is resorted to, it will, during the course of 

 a night, have acted sufficiently to convert the hardest into 

 quite a soft water. Another household convenience which 

 we would strongly recommend to the notice of our readers 

 is the softening ewer, respecting which we are told to put 

 " as much ' Anti-Calcaire ' powder as will go on a shilling, 

 fill with water, and allow it to rest all night." The water 

 in the morning will come out of the tap soft and clear. 



In our next communication we propose to treat of the 

 purification of water in its relation to the pollution of rivers, 

 and trust to be able to show how the great questions of 

 sewage contamination and the utilisation of waste products 

 from the habitations of man and his industries ought to be 

 dealt with, by an examination and brief review of the so- 

 called sanitary sections of the Exhibition. 



NOTES ON COAL. 



By Richard A. Proctor. 



(Contin,ued'_, from p. 255.) 



IT is, in the first place, a remarkable circumstance that 

 although vegetation was certainly not limited to the 

 carboniferous period, yet it was in that period that all the 

 chief coal-fields were formed. There are exceptions, no 

 doubt, t3 this rule. In the times which preceded the car- 

 boniferous period, some coal-seams were formed, and some 

 well-known coal-fields belong to later geological periods. 

 There are beds of true coal belonging to the tertiary period 

 (the latest of the main geological periods) ; and, passing 

 from the oldest tertiary period to our own time, we find 

 instances of the deposition of enormous quantities of lignite 

 and brown coal, as well as of the formation of peat, which 

 must be regarded as only needing submersion and conse- 

 quent pressure to become, in the lapse of time, either true 

 coal or verj- near akin to it.f Yet, it remains true that 



* Loc. cit., p. 30. 



t"Xear the surface," says Professor Ansted, "this substance 

 (peat) is light-coloured and spongy, and the vegetable matter is 

 little altered ; deeper, it is brown, dense, and decomposed ; at the 

 bottom, it is black, and nearly as dense as coal." As a fuel, how- 

 ever, peat contains much ash. The same is true of lignite and 

 brown coal. Moreover, brown coal is injured by exposure to the 

 weather, which is not the case with true coal. Lignite splits in the 

 air ; brown coal falls to powder. 



