4S2 Mr. '3['v Graham on the Refuse Lime of Gas-works. 



for th'6 absetiC6 of ammonia and cyanogen compounds. The 

 lime had not been exposed more than a few hours to the air 

 before it was operated upon. Still, to my surprise, it did not 

 blacken an acid salt of lead, and contained no sulphuret of 

 ttalciwirt. ' It was not dried, but analysed in a damp stat6) 

 exactly as it is sent out of the works to be used as mantHFel '- 



n.u.M.,./ . > Composition ofQff^.f^e_,^^^^^^^ ^^j, ^^^r^ 



Xd ^Jiiirqlc Hyposulphite of lun^^^i g^rf .9mil^(39jirfqlH8oqY,ri 

 4m rijiw b'> Sulphite of lime ,i3,iW. fCiohnM^jio slgnia 'a 

 oJni baJouL Sulphate ot lime jj|,jo£i,ina avome^'^Q hioB oiioriq 

 loi oldeJior Carbonate oHimea^j eblm^- 1**48 Mq-gmil ad) 

 -nBU[) ni ao! Hydrate ,Qf,|ijin,^i noiJB^Bqo'K.f ^. .^^'^^doqioq arrij 

 ni 92fj liDdi Sulphurj-B.^jjHjjTi^j^^lPfji siOHi 3di ;|s^HAoD9d ai ^iii 

 bailqqB ad ' Sand . . .• . . -frioifidd ' ''^ ^i alq-otio^h 

 lavlialo 91 Water combined . o-naiJDf 8*4i> oJ^^bg-.Bl. 



Water (free) 23-79. jsvlia nroii 



100- 



With no more than a trace of ammonia and cyanogen. ^-„ 

 '^ The lime in the porous condition in which it is takenfrom 

 the dry-lime purifiers, absorbs oxygen so rapidly from the 

 air as to heat, and hence the state of oxidation in which the 

 sulphur is found. If the lime be very damp, or diffused 

 through a quantity of water, as it comes from the wet-lime 

 purifiers, then the absorption of oxygen is much slower. The 

 fluid portion then contains in solution the bisulphuret of cal- 

 cium of Herschel, which may be crystallized from it ; and at 

 first very little else. 



.\^; After the first rapid absorption of oxygen, the further oxi- 

 *daliou of the gas- lime is decidedly slow. A specimen keptjp 

 an open vessel, and repeatedly moistened and rubbed to powfr 

 der when it dried, was found after three months' exposure to 

 retain 7 per cent, of sulphurous acid, besides all the free sul- 

 phur originally present. The hyposulphurous acid had en- 

 tirely disappeared. Hence, if added to soil as manure, gas- 

 lime must be powerfully deoxidizing, a property which will 

 generally impair its utility. 



ju It appears advisable, where the refuse-lime does not possess 

 any value from ammonia, to dry it strongly, or roast it. It 

 would thereafter consist of nearly equal weights of sulphate 

 and carbonate of lime, and be in the condition most valuable 

 d.'j a manure. 



^•f Refuse-lime, such as was examined, may be recommended 

 as a convenient and most oeconomical source of the hyposul- 

 phites. The lime, after being taken from the purifiers, should 

 be exposed to air for two or three days, till it loses all smell 



