36 



* KNOWLEDGE * 



[Nov. i, 1385, 



the pressure communicated thereto. When the consumption or 

 dr.auglit upon the ni.ains diminishes, the pressure therein increases, 

 wliich raises the liolder, and consequently lifts the water in the 

 chambers above the level ot the water in outer annular tank. The 

 result is that water flows back from the ch.ambers through the 

 syphon, returning to the tank, removing the weight from the holder, 

 and consequently diminishing the pressure. The action at first sight 

 appears somewhat paradoxical, since the increase of pressure is made 

 to produce a decrease, and the decrease is made to produce an 

 increase. By dividing the air-vessel into chambers of various 

 widths and making the proper combination, a maximum 

 pres.sure of any number of tenths, depending upon tlie 

 depth of the float, may be obtained. If it be desired 

 that the pressure shall not begin to increase until the valve 

 has opened to <a given extent, it may be accomplished by 

 lowering the water in the outer tank to the level at whicli 

 it is required the increase should commence. If it be desired 

 that the increase of pressure should cease on a given pressure 

 being obtained, it is accomplished in the following manner: — 

 Supposing the area of outer annular tank D equals area of gas- 

 holder of Governor, then for every tentli of an inch of water 

 transmitted from D to holder there will be one-tenth pressure com- 

 municated to Governor. H is a vertical pipe (reaching above level 

 of water) in which syphon ascends and descends. J is a pipe com- 

 municating with bottom ot H, having a gland at top in which a 

 smaller pipe G, carrying a scale divided into tenths, slides water- 

 tight, so as to be adjustable to any height. Let it be required to 

 limit the increase of pressure to twelve-tenths. Slide G into J until 

 its bell-mouth top is just twelve-tenths below level of water, as in- 

 dicated by scale when holder is at its maximum height, that is, at 

 the period of minimum consumption. It is obvious that when 

 twelve-tenths depth of water, which produces twelve-tenths pressure 

 on governor, has been transmitted from outer tank to holder, no 

 further transmission can take place, however much farther the 

 holder and syphon may descend, since the water, which can only 

 reach the syphon through G, has descended to the level of top 

 thereof. If it is desired to vary the rate of increase of pressure as 

 the valve descends, it may be accomplished by .uniting tlie curve or 

 shape of the valve to tlie required variation. 



Instead of the syphon for conveying the water from tank to 

 annular chambers of float, a flexible pipe F may be employed. 



Wlien the apparatus has been adjusted to suit the gas supply of 

 any sj-stem of mains, it will be seen that, with a uniform inlet 

 pressure, a given opening of the valve will always be accompanied 

 by the same outlet pressure ; and since a given orifice, with a given 

 pressure, discharges a certain known quantity of gas per hour, an 

 indication either of the extent ot the opening of the valve or of the 

 degree of outlet pressure will be an indication of the rate of 

 discharge. 



CLEANING KITCHENERS. 



[Patent No. 5,126. 1884.]-Mr. L. Mills, ot "I, West-street, 

 Gravescnd, has patented a plan for doing away with the dirty and 

 unpleasant method at present in use for cleaning tlie flues of 

 kitcheners and other ranges. It consists of a number of scrapers 

 which are pivoted on the surfaces to be cleaned, and which are 

 operated by handles placed in convenient places outside the grate. 

 The scrapers, after removing the soot, automatically push open the 

 soot-door and expo,l the soot. 



ELECTRIC METERS. 



[Patent No. 9,801. 1884.]-Mr. F. W.alker. ot .'ifi, Spondon-road, 

 Tottenham, has patented a method ot measuring the strength of a 

 current of electricity flowing through a circuit, consisting of a low- 

 resistance series solenoid and a high-resistance shunt solenoid ; 

 the latter solenoid is movable inside the former, and passes over a 

 fixed iron core. When the current passes, the high-resistance sole- 

 noid is drawn into the other solenoid against a spiral spring of 

 gauged tension. A lever with its fulcrum is attached to the high- 

 resistance solenoid, and carries a stylus which traces upon a 

 rotating drum a curve from which the electrical energy can be 

 obtained. In another form each of the two solenoids has a move- 

 able iron core attached to a lever carrying a stylus. Two curves are 

 thus produced, one indicating the electro-motive force, and the 

 other the current strength, the sum of the two curves at any ordi- 

 nate representing the electrical energy. 



PURIFYING PARAFFIN OILS. 



[Patent No. l.S,44fi. 1884.]— This invention is by Mr. G. T. 

 Ceilbj-, of Midcalder, Midlothian. Shale or similar oils are mixed 



with alcoholic solution ot caustic soda ; this falls to the bottom, 

 carrying with it the impurities. The supernatant oil contains an 

 appreciable amount of alcohol, whicli is separated by distillation. 

 The tarry matter mi.xed with the soda is steamed in a dephlegmating 

 column to recover the remainder of the alcohol. 



ITr. E. A. Proctor's Lecture Tour. 



1885-0. 



1. LIFE OF WORLDS 



2. THE UNIVERSE 



3. THE SUN 



4. THE MOON 



Siihjpcts : 



:,. COMETS AND METEORS 

 C. THE STAR DEPTHS 



7. NEW STARS. 



8. VOLCANOES 



9. THE GREAT PYRAMID. 



Uacli Li'Ctiire is profiisehj illustrated. 



All communications respecting terms and vacant dales should be 

 addressed to the Manager of the Tour, Mr. JOHN STUART, Royal 

 Concert Hall, St. Leonards-on-Sea. 



Nov. 2, Chester ; Nov. 3, Sale ; Nov. 4, Bnrnley ; Nov. 5, G, 7, 

 Southport ; Nov. 9, Stafford; Nov. 10, Streatham ; Nov. 11, 13, 

 Sunderland; Nov. 12, Middlesbrough; Nov. 1.5, Newcastle; Nov. 

 16, Oldham; Nov. 17, Darwen ; Nov. 19, Saitaire; Nov. 20, Harrow; 

 Nov. 23, Bow and Bromley Institute ; Nov. 24, Trowbridge ; Nov. 25, 

 28, Bath ; Nov. 26, 30, Clifton. 



Dec. 1, AVeston-super-Mare; Dec. 2, 5, Bath; Dec. 4, Clifton; 



Dec. 7, 8, 9, Croydon ; Dec. 10, Alderley Edge; Dec. 11, Chester; 



Dec. 14, Dorchester; Dec. 15, Weymouth ;" Dec. 16, 17, IS, 19, 

 Leamington. 



Jan. 4, 6, 8, Barrow-in-Furness; Jan. 11, 13, 14, Carlisle; Jan. 12, 

 Hull ; Jan. 15, Stockton ; Jan. 18 to 22, Gilchrist Lectures ; Jan. 26, 

 Bradford ; Jan. 27, Busby (Glasgow) ; Jan, 28, 29, 30, Edinburgh. 



Feb. 1, 2, Edinburgh; Feb, 3, Alexandria; Feb. 4, Rothesay; 

 Feb. 5, Chester; Feb. 6, 2(», Malvern ; Feb. 8, 12, 19, Cheltenham ; 

 Feb. 9, Hereford ; Feb. 10, Walsall ; Feb. 1 1, Wolverhampton ; Feb. 

 15, Upper Clapton ; Feb. 17, Reigate; Feb. 18, 25, London Institu- 

 tion ; Feb. 22, Sutton Cold field ; "Feb. 23, Uttoxeter. 



March 1, 3, 5, Maidstone; March .3 (afternoon) and March 

 (afternoon), Tunbridge Wells : March 8, 11, 13, 16, Belfast ; JIarch 

 8 to 27, in Ireland; March 29 to April 2, Gilchrist Lectures. 



NOTICES. 



KxoWLEDGE October Xumbeks (205, 206, and 207) have uot been inrluileil in 

 anv monthly part, Imt form part of Vol. Vlll., the lust number containing the 

 index to the Volume. These three numbera run be obtained either through an 

 agent or direct from the Pul>li3her, prii'c ;id each, post-free. 



The foUowiug numbers are out of print, viz. :— Xos. 1 to 13, 16, 17, 20, 21, 22, 23, 

 26, 27, 28, 29, 31, 32. 33, 3J, 36, 49, 50, r.l, 53. 60, 62, 63, 79. All other nundier^ are 

 to be had on application to the Publisher, price 3^d., post free. 



Vols. I. and II. are entirely out of print ; Vols. III. and IV. (Jan. to Dec, 

 1383), 73. ed. earh : A'ola. A'., "VI., and VII. (Jan. 18S4, to June, ISiUS), 9s. cuch. 

 Vol. VIIl. (now ready), July 3 to Oct. Hi, iS-io, 7s. 



Binding Cases for all Ihe Voliimea putdished arc to be had, price 2s. each; 

 iueludiug parcel postage, 2s. 3d. 



Subscribers' numbers bound (including title, index, and case) for 3a. ea^h 

 A'olume ; including return Journey per parcels post, 3s. 9d. 



Kemittances should in every case accompany parcels for binding. 



TEBMS OF SUBSGBIPTION. 



9. 



To any address in the United Kingdom, the Continent, United 



States of America, and Canad* 7 



To Australia, New Zealand, and South Africa 8 



To the Enst Indies, China, &c. (viii Biindiii) 9 



All subscriptions arc payable in advance. 



