242 



KNOV^LEDGE 



[Sept. 19, 1884. 



THE SOFTENING OF WATER. 



Our inquiries into the necessary pro]5erties of potable 

 ■water led us to refer to its softness orly incidentally. We 

 have shown that the value of water for the table and the 

 kitchen does not depend essentially upon its hardness or 

 softness. That a very hard water (from 14 to 16 degrees) 

 is undesirable, cannot be disputed ; the fur in kettles and 

 the delicate mucous membranes of the human alimentary 

 canal would alike rebel against its extensive employment. 

 On the other hand, we gave as an instance the sad experi- 

 ences of one of our correspondents, whose parishioners suf- 

 fered from lead-poisoning, indirectly due to the very soft 

 water of his district. Taking all things into consideration, 

 we deem it advisable that a water, to be thoroughly whole 

 «ome for the majority, ought to contain a certain amount 

 i(from y to 7 degrees or thereabouts) of hardness. The 

 softening processes employed by the water companies of 

 hard-water districts, added to effective filtration, such as 

 that insured by the use of Maignen's " Filtre llapide," does 

 not leave anything to l>e desired in a supply of good and 

 pure water for drinking and cooking. 



But let us turn for a moment to other branches of the 

 household ; we would find not only the laundress and 

 scullery-maid up in arms against us, but we ourselves 

 would feel disposed to admit that they are not unreasonable 

 in their outcries, when we rise to wash with hard water. 

 These inconveniences, however, are but trivial when com- 

 pared with the serious drawbacks which present them- 

 selves to the engineer and manufacturer in a sufjply of 

 moderately hard water. It would seem somewhat contra- 

 dictory to state that it is not the hardness per se which is 

 objectionable, but rather the presence of the ingredients 

 which cause that hardness. Yet it is easy to show that 

 when the water is merely treated so as to remove hardness 

 without eliminating the cau-es thereof, such as the intro- 

 duction of anti-crustation compounds, little or no good 

 follows. As the supply of rain wat- r is a most fluctuating 

 quantity, it cannot be relied upon ; and as distilled water 

 cannot always be procured in sufliciency without enormous 

 expenditure, the engineer and manufacturer are forced to 

 look to springs, wells, and rivers for their supplies of 

 water, and to contend against (I'mjiorar;/ hardness, due 

 chiefly to the carbonates of lime and magnesia, and to a 

 less degree to iron, alkaline earths, chloride of calcium, 

 alumina, silica, and silicates ; and per)iin»fnf, hardness 

 which arises from the presences of the suli)hates of lime 

 and magnesia. 



In steam-boilers these various products are deposited, 

 and become a constant source of anxiety, in the form of 

 hard incrustations and granular deposits The former have 

 to be periodically chipped away, or else the boiler wotild 

 soon cease to act as such, owing to the bad conductivity of 

 the incrustation layer ; and if things are neglected slill 

 further, the metal plates become heated to redness, the 

 overlaying deposit cracks, the cold water comes suddenly 

 into contact with the red-hot surface, an enormous volume 

 of steam is generated, and the inevitable consequence is a 

 serious explosion. The periodical chipping off of the de- 

 posit, too, gives rise to a proportionate wear and tear, 

 which obviously would be saved by the use of water freed 

 from dissolved salts. The granular deposits also help to 

 disturb the tranquillity of the engineer, by wasting his fuel, 

 for they raise the boiling-point of the water in which they 

 are dissolved ; and when deposited they have a nasty habit 

 of .shifting along the convection currents in the boiler to 

 some inconvenient or dangerous position, where they may 

 behave in a manner analogous to the incrustation explosion. 

 Even where this is provided for by the shai^e of the boiler, 



whereby they are forced to occupy some spot protected 

 from the fire, they are prone to blow over as a fine dust 

 along with the steam into the pipes, or even into the 

 cylinders, and then cause dreadful havoc amidst slide-valves 

 and other internal working parts of the engine. 



The manufacturers of woollen goods, bleachers, dyers, 

 and others, are all well aware of the evil influences of hard 

 water. It wastes their soap, and keeps their fabrics rough 

 and insusceptible to after-processes. Tanners find that it 

 blocks up the pores of their skins with carbonate of lime, 

 which impedes the subsequent treatment of dyeing the 

 leather, and, by rendering it prone to damp, results in the 

 pn duction of an inferior, unstaWe article. Sugar refiners, 

 brewers, and distillers are equally alive to the disadvan- 

 tages of hard water, for not only does it retard the pro- 

 cesses of their manufactures, but renders them inferior in 

 quality, and adds to their expense by undue wear and tear 

 of machinery. 



In our next communication we shall have occasion to 

 draw the attention of our readers to some of the most 

 valuable and recent advances which have been made in 

 this important branch of the water-supply question, advances 

 which, we are glad to say, are well represented at the 

 Exhibition. 



DR. KINNS AND HIS FRIEXDS. 



IN order to remove any possible misconception in con- 

 nection with Dr. Kinns, I would add to what I said on 

 p. 222, that the testimony of Dr. Birch and Mr. Pinches 

 to the entire accuracy of his historical facts is, of course, 

 that of two eminent members of the staff' of the British 

 Museum. As Dr. Kinns never professed that they testified 

 to his scientific facts, I cannot myself conceive how any 

 suspicion of untruthfulness could ever have been attached 

 to him, whose title to respect is so thoroughly testified to 

 by the names of his committee. 



I think that I ought perhaps to add, too, that my 

 description of Mr. Lynn as having " occupied a sub- 

 ordinate position in the Royal Observatory " may have 

 given an inadequate idea of the status of a gentleman who 

 was not only Superintendent of the Altazimuth, but also 

 of the Calculating Dejiartment at Gieenwich for many 

 years. As an authority on the facts of astronomy, Mr. 

 Lynn is unimpeachaVile. T^i him, it will be remembered, 

 is mainly due the reclamation for Cassini of the discovery 

 of the chief division in Saturn's ring, which had been 

 erroneously attributed to Ball ever since the time of Dr. 

 Kitchiner. 



And I may further say that, in expressing my dissent 

 from the action of Dr. Kinns's committee, I did so before 

 the reperusal of his work, " Moses and Geology," which 

 has led me to note its perfect accuracy. I therefore now 

 witlidraw all I then stated of an unfavourable character, 

 and wish both them and Dr. Kinns God-speed ! 



Having thus endeavoured to set myself right with all 

 conceined, I am glad to find, by the accompanying note, 

 that Dr. Kinns and his committee are satisfied with my 

 amende Itonorahle. — Acting Ed. 



To the Editor of Knowledge. 



The College, Highbnry New Park, 15 Sept., 1S84. 

 Deak Sik, — Permit me to express, on behalf of my committee 

 and myself, our thorough appreciation of the honoHrable and 

 gentlemanly manner in which you have withdrawn all the nnfavonr- 

 able statements you inadvertently made in reference to ourselves 

 in one or two of your previous editions. — With moch esteem, 

 I am, 



Yours most truly, 



Samuel Kixss. 



