l62 



SCIENCE. 



[Vol. XVI. No. 398 



SCIENCE; 



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Vol. XVI. NEW YORK, Septejdjek 19, 1890. No. 398. 



CONTENTS: 



The Time-Relations of Mental 

 Phenomena. Joseph Jastrow. . 155 



MoDEKN Explosives and Fluid 

 Fuels 157 



Health Matters. 



Danger in Exercise 159 



Decrease of Tuberculosis in Eng- 

 land ' 159 



Notes and News 160 



Low Water in Boilehs 162 



Letters to the Editor. 

 Dr^A. Graham Bell's Studies on 

 the Deaf. W. G. Jenkins ; E. 



D. Cope 163 



The "Barking Sands" of the 

 Islands. 



B. C. Bolton 163 

 Book-Reviews. 

 Civil Government in the United 



States 164 



Die Purcht 164 



Economic and Social History of 



New England 165 



Among the Publishers 166 



LOW WATER IN BOILERS. 



The Manchester Steam Users' Association for the Prevention of 

 Steam-Boiler Explosions and for the Attainment of Economy in 

 the Application of Steam publishes (Manchester, 1889) the report 

 of its chief engineer, Mr. Lavington E. Fletcher, on a series of 

 experiments conducted by him to determine the much-debated 

 question of the advisability of throwing cold water into a steani- 

 boiler in which portions of the heating surfaces had become red- 

 hot through shortness of water. The same investigator had, as 

 early as 1867, performed similar experiments to those here de- 

 scriberl, on simple household boilers, and corroborated a deduction, 

 coming of occasional accidental illustrations of the same phenom- 

 ena, that the introduction of cold water into such boilers may 

 destroy them by producing strain and seam-rips by the great and 

 irregular contraction thus caused. i .The special object of the 

 recent experiments was to ascertain precisely what occurred when 

 the furnace-crowns of fire-box boilers were left bare of water and 

 overheated, and then flooded with feed-water. 



A Lancashire boiler (7 feet diameter, 37 feet long), with furnaces 

 3 feet in diameter and grates 6 feet long, was used for the work. 

 It was of jj inch iron, of ordinary construction, and set in the usual 



' Mechanics' Magazine, May, 1867; London Engineer, March 15, 1867, p. 228. 



manner. Two feed-pipes were used,^ — the one, as commonly 

 arranged, to discharge its contents beliind the bridge; the other 

 a special construction, throwing the water directly upon the 

 crown of the furnace. Suitable barricades and " bom b proof s "■ 

 protected the observers and others from danger in case of ex- 

 plosion. 



Thus arranged, the boiler was subjected to repeated experiment; 

 the water being hlown out below the level of the furnace crown, 

 sometimes to a greater, sometimes to a less extent; the feed water 

 introduced, sometimes by the regular feed-pipe, sometimes by the 

 showering arrangement; the pressures were sometimes high, some- 

 times low; the safety-valves sometimes open, sometimes closed. 

 But in no case was the boiler injured by the introduction of the 

 feed, and no explosion took place. In some instances the furnace- 

 crowns came down; but this was always the effect of pressure, and 

 not of the introduction of cold water, the latter invariably redu- 

 cing the pressure promptly, except where the pressures were 

 initially very low, or neai-ly atmospheric, in which case the intro- 

 duction of the feed- water occasionally caused slight but momen- 

 tary rise of pressure. 



The conclusion of the experimenter is, that " these experiments 

 put to rout the generally entertained ojiinion that showering cold 

 water on red-hot furnace-crowns would cause the ' instantaneous 

 disengagement of an immense volume of steam,' which would act 

 'like gunpowder,' overpowering the safety-valves however effi- 

 cient, tearing the outer shell of the boiler to pieces, and hurling 

 the fragments to a considerable distance." 



The writer of the report goes on to say, " It would have becB 

 well if they had been tried ."ome fifty years ago, in the days when 

 high-pressure steam was young, when the cause of steam-boiler 

 explosions was shrouded in mystery, and the easiest way out of 

 the dilemma was to blame the stoker." But such experiments 

 have been repeatedly tried in earlier years; and some of the most 

 interesting and important, more than a half-century ago, by the 

 Franklin Institute in this country, exhibited precisely tli^ fact.s 

 here again shown. ' The later work of the United States Board 

 of 1875 was but iri-egularly and unsatisfactorily published; but our 

 information, such as it is, leads to nearly the same conclusions, 

 with this important qualification: that while, as a rule, explosion, 

 does not result on introducing feed-water into a red-hot boiler, it 

 nevertheless may, and sometimes does, take place. Mr. Fletcher 

 concludes from these latest experiments that the right thing to 

 do, on discovering low water in a boiler, is to put on the feed at 

 once. 



It would seem that this statement should be given the form, 

 "The probabilities of fatal accident are slight in such cases, and 

 the wiser plan is to at once put on the feed-watet' in full force, 

 then proceed to dampen the fires. We would not draw them ; 

 that being certain to, at least momentarily, greatly increase the 

 heat of the furnace." - 



The report of the Franklin Institute was made to the secretary 

 of the treasury in 1836. The conclusion reached was that the 

 injection of water upon the heated surfaces of the experi- 

 mental boiler produced a sudden and considerable rise of 

 pressure.^ 



The work of the government board led to the conclusion by Dr.. 

 Thurston that " the overheating of the metal of a boiler in conse- 

 quence of low water may or may not produce explosion, accord- 

 ingly as the sheet is more or less weakened, or as the amount of 

 steam made by the overflow of the dry heated area by water is 

 greater or less." ' 



There would seem to be no question, in the light of our present 

 knowledge, that low water, in some cases, may produce, or at 

 least initiate, disastrous explosions; while there is as little doubt 

 that it is only under conditions which are very rare, and very 

 difficult of production, that such result may be expected to occuiv 

 The contribulions of Mr. Fletcher to the literature and the facts 

 of this ioiportant matter are as welcome as they are interesting; 

 and valuable. 



1 Journal Franklin Institute, vol. xvii. 1837. 

 - Thurston's Manual of the Steam-Boiler, p. 614, § 292. 

 • s /i,jd., p. 636. 



■> Ibid., p. 643. See also, especially, pp. 567, 568, arts. 277-279^ 



