t herefore -ueli solutions as sodium. j u it a --mm. or a ninoni um carbona t es 

 form in snlutions of mo-t other salts MX < >y M X ,. in-< iluble ]>re 

 ei}>itates of carbf.-nates of tin- u'ivtm metals M lunivalent metal 

 rcjilai-iiiu 1 I I * or M (bivalent metal ivplaein"; II, ) ihat is, M .,('<>.<, ] 

 M ( ' >... llms a solution 'it barium chloride uives with sodium 

 carl M mat e a precipitate of barium carbonate, l>a(_'n.,. For tin's reason 

 in nature the waters iuin^ from roekv Tonnat ions very often contain 

 carlionales : tor example, calcium, fern ms or magnesium carbonates, iVc. 

 ( 'arbonic anhydride which. like \\"ater, is formed with the develop- 

 ment of a lai'u'c amount of heat is veiy .-table. For this reason very 

 few siib.-,tances are eaj.altle of <!] >ri\ i nij; it of its oxx'^eii. lio\\-e\t-r, 

 ma ^iii'-iii 1 1 1. |iota>^ium and like metals, on heiim' heated, 'uirn in it, 

 ^ejiarat inu r carbon and forming oxides. If a mixture of carbonic- 

 anh\'dride and hvdro^en be ]>assed t hrouudi a heated tube 1 , the format ion 

 of water and carbonic oxide will be observed ; ('< >., + 1 1 , =(.'( ) + 1 1 . .< >. 



-!" 11 tlnit i-. will n uit tin- jin-M'iicc lit' wul i -r tln-y displact 1 it, which clearly >lmws 

 ' tlii- kind h"\v much dc|M-ii(is U|MUI the conditions of reaction and the 

 [IP pert : t he snli-tances formed. These relations, which at lir-t ML:! it appear coin- 

 : .. !:.:;. Ice I.e-t uiidersl ..... 1 if we represent that two salt s. MX and X Y. in ^eiiend 

 ji'.e. iin n- or |e>s. two other -alts. .M Y and NX. and examine the properties of 



t" -oine extent form -odium carhonute and silica. SiO : Idit the latter. 

 . ; the i-c-ma miiiu mass of -odium silicate i- ,i_ain decompo-ed 

 i vdride. -o that the matter terminate.- with the complete -eparalion of 



ic Iln : ation of -odium carl ..... ale. In a t'll>ed state tile case is diiTercnt ; 



eact /. itli CM to form carhc nic unhydride and -odium silicate, 



ii.n \\ill ' place, and the matter willend with the i-omplete -epara- 



ile ami tin- formation ot -oilium silicate. If iml liin;_' i- -eparated 

 pi.en- of the reaction di-t rilmt ion takes place. '1'herefnre. alt lioiiLfh carlionic 



' ' ; id. -till not for this rea-on, I ml only in virtue of it-, LTa-eons form. 

 M, -place it in -aline solutions. The small amount of energy of car- 

 l-r-n.iii forward l" account for it s l>ei m_r sepai at ed from salt s liy 



c!d I I . i owe\.-r. not correct. Such a separation onh depends on the 



pi-..|.e,-!i. -.. and M ,-. ,inp. .iin.U. Th u- a cH ic acid d i -pla ce- ca rl ..... ic anhydride 



c..|. 'I - ........ aiihwlride he pa-seil tliroii.L'li an alcoliolic -olulic ..... f 



: ' . d t.itc t hi ici ! !c ,ie:i| i . ! i P . . ; I M i 1 i i . | ., .! . i -- . 1 1 1 1 1 , -;i 1 I M , | i a t , -,( p, i |'a 1 1 -. 1 ii i I l;_ r 



<|i ' ' ; - ot 1 ...... n pot i nd I'c'imed and nf the react in;_ f siilistal ices 



. < 1-1 n llui ' i : ; ., ' i' i .nip" it inn , ,i the measure ot 



. i . d properties, carl.onic acid il.-n.mjiuM-s certain 

 i 1 In ive-l at ions of Secllem .!! on the -olllt ion 

 .' ( hap. I . Note :;s,c. Still t he ivl.it i\e energy 



.; i. . tin-si CM ,.. . v, Inch ue -hall di^cii - fuitlier on \\ hen 



ot d;-n il.nt ion and ..I \elocit\ "I r, action. '1'he principles of that 

 kind o I ..... pi ."n "! c In n,; c.i i mutual ad i ..... idi a- on -I it now lo I ie accept ed were. 



oii'.'ii! !"il. I'.erth'illet a! the commencement ot the present century, and sometimes 

 n oi ' |{< 1 1 et ! i \'. -.' t" v. Inch \M< v. : , I t urn our attention in the folloivin^ 



