'0 



♦ KNOWLEDGE ♦ 



[Jan. -23, 1885. 



■worJs, a line drawn through the several positions of the 

 sun at mean noon w-ill describe the curves as indicated. 

 For reasons which need not here be stated, the diagram will 

 be found generally correct for one year only out of four ; 

 but, upon the scale by which the diagram is drawn, this 

 error is infinitesimal. It is hardly necessary to state that 

 the principal cause of the variation between mean and 

 apparent time is "the obliquity of the ecliptic to the 

 equinoctial." 



Apparent time is about fifteen minutes slower than mean 

 time about Feb. 10, and about sixteen minutes faster on 

 Oct. 27. They agree about April 15, .June 15, Aug. 31, 

 and Dec. 24. If a well-regulated clock were set by appa- 

 rent time on Oct. 27, it would be about thirty -one minutes 

 faster than apparent time on the following Feb. 10. It 

 will be seen that, under such circumstances, clock-time 

 would vary as much from true sun-time as any clock set by 

 the present system of standard time varies from mean-time 

 at the most extreme point. 



The safe operation of a railway requires that the watches 

 of all its employes upon, or who have occasion to I'efer to, the 

 same trains should always indicate the same moment of 

 time. Rail way-time upon lines running east and west can, 

 of course, never coincide with mean local time except at a 

 single point, and the longer the line of the road the greater 

 will be the variation. Before the recent change to standard 

 time there were several cases where the railroad-time in use 

 diiTered by more than half-an-hour from mean local time at 

 various points. The inhabitants of the surrounding country 

 at such points, having no standard of reference except the 

 railway-clocks, accustomed themselves to and used railway- 

 time without inconvenience, and in a number of instances, 

 where the railway standard was changed from some cause, 

 the people made the same change in their time-pieces. It 

 was import;iut in connection with railway-trains to keep 

 exact time, and for all other purposes any relative time was 

 sufllciently accurate. 



In the early part of the year 1883 there were fifty-three 

 standards of time in use on the railroads and by the people 

 of the United States and Canada. The.se standards governed 

 sections with no definite limits, and \ipon railroad lines were 

 apparently inextricably mixed and interwoven. The con- 

 dition of the matter was abnormal in numerous instances, 

 there being no less than three hundred points where rail- 

 roads, using different standards of time, crossed each other 

 and exchanged ti-affic. At almost every city of importance 

 several standards were used by the railways, and in some 

 cases the city time difTered from any of them. Local 

 jealousies made the chance of efiectiug reform apparently 

 hopeless. Many who warmly favoured standard time 

 regarded the reform as one unlikely to be soon accomplished. 



The solution of the problem necessarily required a close 

 and long-continued study of the peculiarities of the situation. 

 Whatever change was proposed must afl'ect as little as 

 possible the relations which previously existed between 

 railway lines and business communities. 



(To he continued.) 



We have roccired from Messrs. W. & E. Cheshire an engraving 

 executed by them from a drawing by Jlr. Allan Barrand, which as 

 an example of wood-cutting is as delicate and beautiful as any- 

 thing that we have seen. 



Economical Steam Te.amway. — The Dewsbury, Eatley, and Birstal 

 Steam Tramways — the first ever constructed in England — worked 

 by Merryweather 7-in. engines, show in the half-year's working 

 accounts that the total cost of the running of the engines is 

 2'57 pence per mile, and the total expenses of the whole establish- 

 ment, including locomotive charges, 516 pence per mile. This is 

 one of the most economically-worked lines in the country. 



CHAPTERS 



ON MODERN 

 ECONOMY. 



DOMESTIC 



XII.— THE FEAMEWOEK OF THE DWELLING-HOUSE. 

 GENERAL PKINCIPLE.S OF CONSTRUCTION — (continued). 



IN continuation of our observations upon the practical 

 details of the hydraulic system for the removal of 

 excrementitious waste, we may note : — 



(ii.) That the soil-pipe ought to be well ventilated. The 

 ventDating-pipe should bo an upward prolongation of the 

 effluent soil-pipe which leads to the house drain, and should 

 be carried up above the roof of the house ; preferably over 

 the chimney-stack, where it ought to terminate in a suit- 

 able ventilating head. The kind of ventilator known as an 

 " exhaust " or an " induced current," ought to be employed. 

 The extraction of foul air from the pipe should be effected 

 by passive means ; that is to say, the external currents of 

 air, however they may come into contact with the appa- 

 ratus, should not only be prevented from causing a down- 

 ward draft, but, on the contrary, ought to produce an up- 

 ward current, and that without any revolution or other 

 noisy movement of the appliance. This exhaustion of the 

 gaseous contents of pipes is of as great importance to the 

 drainage system as to the thorough ventilation of the 

 general apartments and passages of the house, including 

 its chimneys. 



I'he ventilator should provide: (rr),that at what ever angle 

 the wind strikes its head, such action shall produce a 

 partial vacuum therein, and thus secure a powerful up- 

 ward current and no down-blow ; (i), that a very slight 

 breeze shall be sufficient to induce the vacuum, thereby 

 securing an approximattly continuous upw.<)rd current ; 

 (c), that the apparatus shall be inexpensive, durable, and 

 ornamental : (</), a negative quality i.-^, that it shall not be 

 suViject to any movement — the revolving ventilator is not 

 only a noise-producing invention, but, in consequence of 

 its motion, soon wears away ; it moreover requires a 

 "pretty stiff wind" to set it in action, and during 

 quiescence of the aerial currents, a slight breeze, in striking 

 against its blades, is only sufficient to pass between them 

 and produce a down-blow. 



It is a very common error, amongst even modem 

 builders, to decrease the diameter of the ventilating por- 

 tion of the soil pipe ; such, however, is not in consonance 

 with the laws of sanitary physics, and ought not to be 

 permitted ; the escape of .'^ewer-gas is retarded by the 

 smaller bore of the ascending tube, and is apt to give 

 trouble lower down at the closets and house- sewer traps ; 

 the foul air may even eat holes into the metal pipes, and 

 thus escape at undesirable places. There should always be 

 an inlet for fresh air at the ba'-. of the soil-pipe, on 

 tlie house side of the dip-trap, \.ctween the house and 

 the sewer. We shall give examples of some of the practical 

 arrangements which have been devised to meet these re- 

 quirements in a future communication. 



(iii.) The angle of junction of the soil-pipe with the house- 

 drain ought to be such as to afford a ready passage of the con- 

 tents of the one into the other, or, better still, angles should 

 be altogether avoided, and curved junctions substituted for 

 them. This may seem to be self-evident to most per.^ons, 

 but it is, in fact, a most serious and prevalent cause of 

 obstruction in the sub-household sewerage arrangements 

 of very many tenements. In some cases the angular junc- 

 tion is almost, if not quite, rectangular, and thus affords 

 facility for the accumulation of solid particles, and finally 

 for the occlusion of the drain itself. 



The drain itself ought to have a fall of about one foot 



