. The railroad and engineering journal . precipitate indicates the relative amount of scale-making material. This lest is, of course, crude,anil would hardly take the place of a good chemicalanalysis, but it is much better than nothing. When the water of ammonia cannot easily beprocured, an experiment inay be tried, in the sameway, by dissolving common white soap, or otherpure soap, in a goblet of pure water, and then stir-ring into the glasses of water to be tested a fewteaspoonfuls of this solution. The coinparativeamount of scale-making material in the water willbe shown fjy the amount of c
. The railroad and engineering journal . precipitate indicates the relative amount of scale-making material. This lest is, of course, crude,anil would hardly take the place of a good chemicalanalysis, but it is much better than nothing. When the water of ammonia cannot easily beprocured, an experiment inay be tried, in the sameway, by dissolving common white soap, or otherpure soap, in a goblet of pure water, and then stir-ring into the glasses of water to be tested a fewteaspoonfuls of this solution. The coinparativeamount of scale-making material in the water willbe shown fjy the amount of coagulated matter whichwill be thrown down. Question 720. What are the most commonlyoccurring corrosive niaterials in waters used in boilers? Answer. The most commonly occurring corro-sive materials are sulphates of iron and alumina andchloride of magnesium. The former are universalconstituents of mine drainage. The latter occursmost frequently along the sea-shore. In addition tothis many waters which drain from mines contain ^^^«j^;4^^. Vol. LXin, No. (..J ENGINEERING JOURNAL. 285 large amounts of free sulphuric acid. If any mine drainagegets into the water supply at any place, the use of that watershould be abandoned if possible. Also in ivells along the sea-shore, or on the banks of rivers affected by the tides, chlorideof magnesium is a frequent constituent, and often causes seri-ous corrosion of boilers. Question 721. How are locomotive tendeis supfluil with coal? Ansticr. This is done in a variety of ways. Sometimes thecoal is shoveled from cars alongside of the tender, but this is aslow and laborious method. In other cases iron buckets arefilled with coal at stations and then are hoisted by cranes and are laid in the ordinary way on lop of the girders they willbe exactly level with the tiack which leads up to the turning the girders on the central pivot so that the railswill come exactly in line with the permanent track whichleads up to the pit, the locomotive can
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectrailroa, bookyear1887
