BOLLEY ON ALLOYS OF TIN AND LEAD. VIT.-New experiments on the Dangers arising from the use of Certain Wutersfer feeding Steam Boilers. BY PROFESSOR EOLLEY. IT has hitherto been received as a kind of dogma in chemico- technical literature that waters which when evaporated. denosit nOLLEY ON WATERS FOR FEEDING STEAM BOILER% 33 only the carbonates of lime and magnesia are bettcr adapted for feeding stcam-boilcrs than those which likcwisc yield sulyhate of lime because the latter salt even in amdl quantity imparts to the deposit a stony cohcrcnce whererrs the carbonatcs arc deposited in the form of a soft mud. That serious mischief may arise from the formation of a stony incrustation on the srirface of a boiler is well known whereas the dcposition of mcrcly pul- verulerk mattcr has not hitherto been observed to crcatc much inconvenience.Most of the remedies proposed far thcse evils havc likewise for their object the convcrsion of thc sulphatc of limc into carbonate ; that is to say ; the production of a muddy in placc of a stony deposit; such for example is the action of carbonatc of soda. Since the practice of heating steam boilcrs vith cod has hen introduced into Switzerland many serious disturbanccs liavc hcen observed in the functions of boilers wliich wcre qnitc iinl<nown so long as they were heated with mood. Both old arid ncw boilcrs heated from within (the Cornish or Fairbairn construction) have become red-hot at the uppcr part of the flue ncar the firc-place while the water-gauge showed that tlie lcvel of tlic watcr was several iuahts above the heating surface.The boilcr-platcs started and had to he taken out and rcplaccd by ncw oiics but without any dimiiiution of the evil. The first of these cascs in which as well as in thc sccond I was consulted by thc well-known cnginccring firm of Esch er Wyss arid Co. happcncd in the Canton Zurich. The water used for feeding thc boiler vas taken from the Jcnal~acli on the southcrn declit ity of the Bachtel. Samples from tliff'crcnt parts of the strcam mcrc scnt to mc for csaminntion. Thrcc samples wcre analysetl and yicldcd thc following proportions of sokd mattcr and carbonate of limc In 1 litre. Total solid residue. Car\cnntc of limc. Samplc a. . . 0*2i2 grm. O.22X gi'iri., b. . . 0.232.E , I> '' . . O*.%l..'!G , 0.2010 , The water contained very little organic mattcr ; szdphates wtre entirely absent ; silica alummn magmsia axid allinline salts were present in small quantity only as compared with the carbonate of BOLLEY ON IVA'L'EliS FOR lime.. The water may be dcscribcd as pirc but rathcr liard-thc harducss beiiig of tlic kiiicl callctl twipor';try. It was sugg;cstcd that tlic niiscliict' d~ovoiiiciitioiicd might arisc from tlic circuiiistancc that above tlic 1)liicc at which tlic wtitcr was drawn for fccdiug tlic boilcr tlic rcfiisc water of n bloacli-work was rliscliargcd iiito thc strcain. A lwttlc of' tlic mastc lhicliiiig liqui(i was tlicrcforc 1ilicwi sc sciit fo c csiiiii ii i;it ic iI.It coi i t ai iicd in solntioii quick lime clilorictc of ~id~i~iii aiid a small quantity of decomposcd cliloridc of limc. 011 mixing it with thc water of the stream a stroiigly milky turldity was prodiiccd. So far there was notliing that +lit iiot liavc bccn cspcctcd but at tlic top of tlic liquid in tlic llottlc tlicrc was a laycr of futty mutter; wliich aftcr mising with water soiutioii iii ctlier and cv:y)orntioii remaiiicd in tlic form of n thickish oil. IIow this coinlwativcly largc quaiitity of fatty imttcr got iiito the hlcaching liquid conld not be asccrtained. The boilcr contained a coiisidcrahlc qiiaiitity of a whitish grey pulverulent deposit coiisisting cssciitially of carbonate of limc. By careful searckiug however certain substances were found in it mcchaiiically mixed; viz.black scaly particles of iron ferric oxide aiid adhcring organic matter which became perceptible on hcatiiig and rcd granules which were fonnd to consist of the remains of a red lead cement. The powder separated from the water eshiliitcd a furtlicr peculiarity. When thrown on water it swam on the surface did iiot become wet hut remained in ids place and drg evm cfter prolonged boiling. A portion of this powdcr was well dried on the matcr bath and then treated with ether wliicli extracted a small quantity of fatty matter. The cause of the plienonienon above-mentioncd was now apparent. Tlie pulverulcut dcposit in the boiler completely covercd the licatcd siirfacc of the flue so that this surface did not come in coiitnct with the water.The qiimtity of powder in the 5oilcr was so largc tliat it must have formed a layer several inches t1I i ck . Tlle ftlttp su1,stsnce which had found its way iiito the water sur-rounded the particles of the precipitated carboilate of lime with a lRper zol~icl~ cozslcl not Be wetted by the water; and in consequence of this Ivant of adhesion the powder mas kept floating on the surface. The powder after being treated with ether ad dried FEEDIXG STEAM ESGIKES. sank easily under water and in its original state was easily wetted by alcohol. The preccding investigations did not however afford any precise iiiformntion as to the nature of the fitttp substance. But shortly aftern-ards I was made ncquaintcd with mother accident of exactly the same kirrd wliich happened to a boiler in the Canton Tllurg:Iu.'Hie watcr with whicli this boiler was supplied n-as found to con- tain as a means of two espcriments 0.2417 grm. solid matter per litre 0.045 of which consisted of orgauic matter containing traces of nitrogen. The residue from four or fire litres of this water was 'distilled lyith a slight exccss of clilute sulpliu~~ic acid tlic distillate had a distiiict odour of butyrlc acid. In this boiler also a considerable quantity of whitish pul\-erulent matter mas deposited mliicli so far as I-could ascertain was free from mechanical impurities. This powder also was not wetted by water. On boiling half a pound of it with distilled water and gradually adding carbonate of soda the powder was at length thrown dowr to the bottom and an alkaline liquid was formed; containing the fatty substance in solution.After filtration and concentration it was mixed with a small quantity of hydrochloric acid ;the odour of hutyric acid then became perceptible and small drops of fat mere separated which did not disappear on dilution with water but hy agitation with ether and subsequent evaporation yielded a small quantitv of a nearly odourless oily body. I was at first of opinion tliat the butyric acid might have existed naturally in the water inasmuch as this acid has been found in many waters deriyed from peat-bogs; but on discovering tlie fat insoluble in water I abandoned this view and subsequently learnt from Mr.Jackson Dircctor of the factory of Esclier Wyss and C o. that the water supplied to the boiler was taken from the condenser of another steam-engine and consequently might have derived the fat from that source. It showed however scarcely any turbidity; arid all the results obtained with it led to the conclusion that the quantity of fat contained in it was very small. Practically the origin of the fatty niatter is of little consequence. By my recommendation a small quantity of solution of carbonate of soda was added to the water supplied to the boiler and by this means the inconvenience above described was completely obviated. It likewise ceased when the water was no longer taken from the condenser of the otlier ena. O'ine. J.Xi. NEWLANJM ON-THE CONSTRUCTION OF I regard these experiments as well worthy of attention. That observations of such cases and enquiries into their causes have been previously published I have not been able to iind. Never-theless though various conditions must conspire to produce the result in question it is very probable that such concurrence fre- quently takes place. The results of this investigation may be summed up as follows :-1. When a boiler is fed with water which deposits only carbonates unmixed with sulphates the preseucs of very small quantities of fatty.mattw may cause the deposit to assume a dusty instead of a muddy consistence. Under such circumstances rubbing the inside of the boiler with grease can only do mischief. 2.This pulverulent character of the deposit may cause those portions of the boiler-surface which are strongly heated and. directly covered by the ' powder to become red-hot thereby giving rise to explosions and all their attendant consequences. 3. In such cases as wdl as when the water contains sulphates the addition of a small quantity of carbonate of soda will be found very usefbl. 4. The effect so far as regards the form of the deposit is probably independent of the kind of fuel employed it appears however from the observations hitherto made that the heating of the boiler plates to redness takes place only when the fires are fed with cod this kind of fuel producing a more intense heat in the immediate neighbourhood of the burning mass.