390 



♦ KNOV/LEDGE ♦ 



[May 8, 1885. 



the letter D inverted thus — U, with a small semi-partition 

 projecting downwards frooi the centre above. This partition 

 dips into the water in the trap, and forms a dip-trap with 

 a water-seal of 1^ in. in deptli. 



Where, however, it is found advisable to do away with 

 not only the trap but the pan closet as well, and to have an 

 entirely r.ew tittiug adequately trapped, there cannot be 

 any dispute that a sound stoneware apparatus, combLning 

 all extra appliances, such as means for thorough flushing, 

 traps, and valves, ought to be selected, and we shall there- 

 fore give a few special examples here. At p. 23 of the 

 " Guide to the Sanitary aud Insanitary Houses," which was 

 published last year for the executive council of the " Inter- 

 national Health Exhibition," the requisites of a healthy 

 closet are tersely given thus : — " Good position. Plenty of 

 light and ventilation. Good form of apparatus. Ample 

 water supply, special ' Intercepting cistern.' Hinged seat 

 to be raised when pouring slops into basin. Lead safe iu 

 case of accident, falling to waste-pipe which discharges into 

 open air." From this it will be gathered that the floor 

 underneath the closet is to be protected by a lead safe, the 

 use of which is to provide against accident to the floor and 

 ceiling, if any, of the room beneath through leakage from 

 any of the taps : in this case the waste water from the safe 

 is made to discharge into the open air through a special 

 pipe which acts as a warning pipe, and which ought to be 



provided at its outlet 



with a brass flapper 



to prevent a draught 



from entering under 



the seat. A good 



closet ought also to 



have a hinged seat as 



'S' "^^ stated above, and 



then a " Queensware Slop Top " of approved shape, such as 



that shown at Fig. '25, can be placed below the seat. 



Of other accessories, an " Intercepting Cistern " of 

 approved form holds a most important place. It ought to 

 efiect a careful flushing of the closet and prevent undue 

 waste of water. About two gallons of water ought to be 

 discharged each time by merely pulling the handle or by 

 the action of the seat ; the water ought to continue to flow 

 even after the handle has been released, and the final flush 



Fig. 26. 



should be as strong, if not more powerful, than at its 

 start. The mechanical parts, moreover, ought to be pro- 

 tected fiom the entry of rubbish, such as straw, leaves, 

 <fec., which are liable at all times to clog the working 

 parts ; and lastly, while the flushing is going on, the inter- 

 cepting cistern ought to be refilling. In every case, the 

 pipe between the flushing cistern and the closet should be 



of large size, about li inch in diameter, so as to afTord an 

 easy and effectual downflow of the discharged water. 



We shall not linger here to give a detailed description of 

 the numerous inventions which fulfil all the demands 

 noted above, save to mention one of the best forms hitherto 

 introduced and known as Doulton's Patent " Vacuum " 

 Water- Waste Preventer (Fig. 2G). When the lever H is 

 pulled down, the cylinder B is thereby raised, and draws 

 up a sufficient quantity of water into the mouth to start 

 the annular syphon. The action of this is to cause a dis- 

 charge of two gallons of water, the flushing power of which 

 is greatest at the end of the flow. 



In our next communication we shall give an illustrated 

 description of the working parts of some of the beat 

 varieties of closet apparatus which may be adopted in lieu 

 of existing defective forms. 



THE ORIGIN AND HOME OF THE 

 DIAMOND. 



By W. Jerome Harbison, F.G.S. 



NO substance is more admired, and certainly no sub- 

 stance is more mysterious than the diamond. Up 

 to a hundred years ago it was generally believed to be a 

 peculiar kind of rock crystal, although Newton made a 

 shrewd guess as to its true nature when, from its remark- 

 able power of refracting light, he inferred it to be an 

 " unctuous substance coagulated," classing it with camphor 

 and other bodies which are rich in carbon. 



In 1694, certain members of the Florentine Academy 

 concentrated the rays of the sun, by means of a powerful 

 lens, upon a small diamond, and were surprised to see the 

 precious stone become gradually smaller, until at last it 

 disappeared altogether. 



But the great French chemist Lavoisier set at rest all 

 doubts as to the true chemical composition of the diamond 

 when, in 1777, he burnt it in a confined portion of air, 

 and found that nothing but carbonic acid gas re-sulted from 

 its combustion. Carbonic acid gas is a compound of 

 oxygen and carbon — the air had furnished the oxygen, and 

 the diamond the carbon. Great hopes were now enter- 

 tained that diamonds might be made by the bushel ; and 

 there are so many useful purposes to which this hardest of 

 all known substances might be applied, if it could be more 

 cheaply obtained, that such a discovery is a very desirable 

 one. But although more than a century has now elapsed 

 since Lavoisier's discovery, all attempts to manufacture 

 diamonds have practically been failures. The reason of 

 this is that the diamond is crystallised carbon. Now, to 

 obtain a substance in the crystalline condition, it is gene- 

 rally necessary either to dissolve it or to melt it. But 

 carbon will not melt under the greatest heat to which we 

 have hitherto been able to subject it ; neither is there any 

 known solvent for it. 



Of the many attempts which have been made by skilled 

 chemists to produce artificial diamonds, the only success 

 belongs to Mr. J. B. Hannay, of Glasgow. In the year 

 1880 this gentleman announced that he had succeeded in 

 preparing extremely small specimens of crystallised carbon. 

 Mr. Hannay's method consisted in subjecting a hydro- 

 carbon to a red heat at the same time that it was under a 

 great pressure, in the presence of a stable compound con- 

 taining nitrogen. For this purpose he placed some bone- 

 oil with a little of the metal lithium in a stout iron 

 tube 4 in inches external diameter, but having a bore 

 of only half-an-inch. The ends of the tube were welded 

 up, and it was then placed in a furnace and kept 



