April 3, 1SS5.] 



♦ KNOWLEDGE ♦ 



279 



■which the sun is travelling. If it were certain that the 

 ■whole system of st;n-3 were circling around some centre, 

 and if the Milky Way in reality represented the main 

 body of a system of stars (strewn with tolerable uniformity 

 throughout its extent) then it would follow that the centre 

 motion lies somewhere In or near the Milky Way (as seen 

 from the sun). Therefore it would t'ollow V at the central 

 star, if there is any, must He at or near one of those two 

 parts of the Milky Way which lie at right angles to the 

 direction in which the sun is travi 1 ing. This would bring 

 us to -.he constellation Perseus ov. one side and to the con- 

 stellation Scorpio on the other. It was reasoning thus, 

 and lH>cause the remarkable star-group the Pleiades lay 

 near P-seus, that Madler arrived at the conclusion that 

 the centre of the stellar system, around which all the stars 

 revolve, may lie within the Pleiades and be — perhaps — 

 Alcyone, the chief of that group. Ho noted further, that if 

 there were a centre rouiul which all the .stars were travel- 

 ling, then the velocities of motion would be less and less 

 (not greater and greater, as in the solar system) the nearer 

 the centre were approached, and so showed that the stars 

 towards the centre ought all to seem to drift in one direc- 

 tion. He found that the stars round the Pleiades all have 

 a general drift in one direction. Therefore, he concluded 

 that there must be the centre of motion, presumably the 

 very star Alcyone. And now let us see what is the real 

 strength of this chain of reasoning. To be worth any- 

 thing, every link of the chain should be sound. As a 

 matter of fact, not a single link is worth anything. It is 

 not only not certain that the sun is travelling on a nearly 

 circular course, but almost certain that the sun cannot so 

 traveL It is not certain that the whole system of suns is 

 circling round a centre, but impossible that such a system 

 can have a single centre of motion. It is not certain that 

 the stars of the galaxy form the main body of a system of 

 sun streams, as Sir W. Herschell originally supposed 

 ■with tolerable uniformity throughout a single system, but 

 it has been practically demonstrated that the stars of the 

 Milky Way are arranged very differently from those in 

 our neighbourhood, of which the sun is one. And, lastly, 

 the one piece of positive evidence on which Madler based 

 his special conclusion has been shown to be altogether 

 valueless, by the circumstance that precisely the same kind 

 of star-drift which he recognised in the neighbourhood of 

 the Pleiades exists in other regions — Gemini, Leo, Ursa 

 Major, and elsewhere. Thus the whole chain of reasoning 

 is found to be valueless. There remains not a thread of 

 .evidence in support of the idea that there is a central sun 

 around which the whole universe of stars revolves. — N^ew- 

 castle Weekly Chronicle. 



FIRE WASTE. 



MR. C. J. HEXAMER has been delivering a series of 

 lectures before the Franklin Institute of Phila- 

 delphia on the fire waste of the country. 



His lectures have received considerable attention, and 

 the Fireman's Journal of New York, from ■whose columns 

 the following is extracted, considers Mr. Hexamer's lec- 

 tures full of practical suggestions. One of his lectures 

 ■was on " Fires in Textile !Mills," the special feature of it 

 being on the construction of such mills ■with a view to fire 

 prevention. The lecturer said that one of the most impor- 

 tant precautions to be observed in erecting mills was to 

 insure the confining of a fire to the apartment in which it 

 originates. All stairways and elevators should be built in 

 a shaft beside the building proper, the openings between 

 them being shut ofT at the difl'erent floors by iron doors. 



The next precaution to bo observed is in the construction 

 of the floors. The l)est form of fire-pioof floors is of brick 

 arches built between iron girders placed at short distances. 

 Floors of concrete or " terra cotta lumber," a pDrous clay 

 material that can be readily cut and .shaped with edge tools, 

 rank next in security. If ceilings arc of wood, they may be 

 covered with fine wire netting, and plastered over, or they 

 maybe rendered practically "fireproof" by coating with 

 asbestos paint or by liberal and frequent applications of 

 common lime whitewash. Additional loss is frequently 

 caused by having floor-beams so deeply embedded in the 

 side walls that when they burn through in the middle the 

 weight upon them causes the overthrow of the walls when 

 the floors fall in. This can be easily avoided by placing the 

 Joists so that they fall out when burned through in the 

 middle. Fire doors are best made of heavy wood, covered 

 on both sides with sheet-iron, and fastened to the brick wall. 

 Two fruitful causes of fires in mills are the lighting and 

 heating arrangements. Hot-water pipes are tho safest, 

 steam-pipes ranking next. To avoid having combustibles 

 placed in contact with them, they should bo suspended 

 from the ceiling, where they are out of the ■way, and give 

 the best heating results. Mr. Hexamer claimed for the 

 incandescent electric light superiority over all other methods 

 of illumination. 



CHAPTERS ON MODERN DOMESTIC 

 ECONOMY. 



XXI.— THE FRAMEWORK OP THE DWELLINGHOUSE. 



STRUCTURAL EXAMPLES (continued). 



TUE DISPOSAL OP HOUSEHOLD REFUSE. 



"\TTE shall now pass on to the details of the hydraulic 

 VV system of sewerage in so far as it bears upon the 

 domestic drains and their accessories. To obtain security 

 from sewer gas has been the chief aim of modern sani- 

 tarians aod inventors, and it has at length been recognised 

 that, provided the channels for conveying away waste 

 products are thoroughly sound and suitably placed, perfect 

 immunity from foul air in the house will additionally 

 depend upon {a) suitable disconnection of the house-drain 

 from the public sewer ; {!>) relief of undue pressure upon 

 traps by the establishment of an efficient system of ventila- 

 tion, which shall provide for a constant supply of fresh air 

 to the drain and all the pipes, and the constant removal of 

 vitiated air therefrom at a place where it cannot afTect the 

 sanitary condition of the abode ; (c) a sullicient, yet not 

 too great, fall of the pipes, to ensure a speedy removal of 

 their contents to the common sewer, aided, if necessary, 

 by adequate flushing apparatus. As sewer-gas is not gene- 

 rated until decomposition sets in, and as decomposition of 

 excrementitious waste does not commence until after several 

 hours have passed, it follows that attention to the precepts 

 last mentioned cannot fail to secure the desired result. 



In a former chapter we noted thrtt the chief cause of 

 insecurity and leakage from the house-drain could be traced 

 to its imperfect jointing. We condemned the use of clay 

 for rf asons which we gave somewhat fully. We are now 

 inclined to condemn the use of even a good hydraulic 

 cement, because it is open at all times to contraction and 

 expansion, which, though but slight, is still sufficient to 

 give rise to leakage ; then again, cement is liable to give 

 way during the settlement of tfie drain which may take 

 place long after it has been carefully laid and tested. 

 Although much can be done to prevent this settling of the 

 drain by the preparation of a good foundation for it to rest 



