NEW BOOKS Vorlesungen iiber theoretische und physikalische Chemie. By J . H . i f n n ' f H o f . Porf I,Chciiiirtzl Dyirnuiit-s ; 7j x 2.3 r i l l ; p p . .i-ii nuti 2j2. Emzrlisrhiifeig : F. 1 *ieafecqiiiid Sohit, rcc9- every one for it is the 1no-t corriplete treatment to 1)e foutitl :iii~.~\-liere,The results. of cour>e. are mostly negative ; h i t a clear 5tatement o f our ignorance is always the preliiiiinary step to dispelling that igiioraiice. 'rlie revie\\-eris a little scepi.ica1 215 to tlie real iiiiportaiice of viscosity. tliougli that itenis to lie the directioii in \c.liich mobt people are orkiiig. Some of the novelties it1 t h e hook art. t h e coniplete preh.;ure-teti~perature tliagratii f x a ;alt ailti ivater, 11. -;J : the tliagrani for ether ant1 water, p. 39 : the qiiehtioii of the non-esisteiice of iiitertriecli:iie Ii!-tlrates. p. ,i;; tlie use of the ttrni " 1i:ilf-electrolyte" for ~ v e a kacitls aiitl 11 , p. I I z : the tiiscussion of falhe equiIi1)riiini. 11. 20s. The hook is a valualile aiitri1)utio:i to scientific literature. I t \v itself \\-hat t h e author wishttl it to l ~ e ,' ' a help to those u.110 n k l i esp learii the latest acliievemeni s of physical chemistry. ' ' 1Viidcr 0. Rtriicrqf'f Lecons de Chimie geniarale.-f?j, f'. Schiit=ciihcl.gci'. Etiitc-tr' h j , 0.I ? u / f do/i!ird. I; X 2.t ciii : pp. zmiii 1 i i 2 i i j c T 6 . ZJ!zri.q ; 0. J I u i n , rccyLS. Pri(.z;p a p t * i . ioji-triics.-Tliis voluiiit coiitains the lectures oii general clitiiiistry tleliveretl ljy ScIiiitzeii1)erger at t h e Co//l:,?edr Fmiz~~e,H e liatl ali\-ays iiiteii~letlto publisli thein aiitl. after his death. they \Yere edited by his former assistant. Routlouartl. Tlie heatliiigs o f t h e fifteen di:ipters are as follo\vs : I , Clieniical I'henoirit-11a : 2 , Cheinical Equililiria ; 3 , \-olutiie ant1 TVeight Relations for Cotnpountls ; 4, I)eteriiiination of Equi\-aleiits ant1 of .4toiiiic TVeiglits : -ear; ago they ha\-e not yet 1i;itl inucli effect u p i i the writers of testbooks. The o n l y hooks that treat tlie !subject from liii point of view are his I'o~~it~.ci!~~~ys.ci/ ~ i h r i .I ) ~ f f ' e . i ~ ~ ~ i i f i t z / , q - / ~ ~ i piihlislietl c / / / ~ i ~ , ~ - in c ~ z rS9 , I , zinc1 tlie hook hefore us. This 1)ool; gi\ e5 i n ii stiinll coiri~iassaii(1 iii c l e x outline tlie niaiii features ~f the tlieijry :IS prt.seentetl in the I iii./c,sni/,yeir : tlie lie:i\-iiiws i i t i t l prolixit!- of tlie original lia\-e liean avoitlt(1, atid iiisten(1 of giviiig 2411 the kiio\m proofs ( i f e:icli tlic.,reiri. tlie .impleu1iseciiiciit iapter I11 tile funtlanieiitd theorvriis i i i I.ie.5 theory ~f t h e one-paraineter group arc given. and tlicse are enipio>-erl i n Ckipter 11-to explaiii tlie coiiiiectioii that exists ljet\r-et.ii the infiiiite~itnnl trniisfr)riiiation of a group i i i i i l :III iiitegratiiig iactor of the c(irre>pii(liiigrlifferenti:il eqtiatioii. Chapter 'L. coiitaiiis Lie's geometrical iiiterliretatioii of tlir i i i t e g a t i i i g factor, an11it. appiicatioii to pr:dleI mil to isotliivmal curves. Cliapter 1.1 gives tlie usiial tiietliotls for t h e iiitegratioii of equation. of the first ortlcr ])ut tiot o f tlie first ilegree. It ~ 1 i contains 0 a very siiiiple inetliocl. rlue to tlie a).itlior, for fiiiiliiig t h e s i i i p l a r holution Ileii :i group is ktio\\-ii uiiiler which tlie equntioii is invariaiit. Chapters 1-11n n r l 1.111 are rlevi~tetlrespccti\-elJ- to tlie cqu:itioiis of Iticcati a i i t l of Clairnut. ali(1 to total tliffr.rciitia1 equatioiii i i i three vciri:il)Ie*, Chapter5 I S :iiitl S take u p ortliiinry tliffvreiitial equatioiis of the. ~ e c o n i lorilcr aii(l o f tlie iwtli oriler. mitl Lie's tiietlioils ai-e eiiiplo!.ctl to ;lio\r that iii certaiii ciiheh the orrler of the equatioii can lie tliiniiiislietl 1)y uiiity. C1i:iliter S I coiitaiiis the ii5ual tli,scii.4oii of tlie linear tlifferciitial eqii:itioii \\-ith ci,ii.t'iiit coefficients. ant1 also tlic :ipplicntioii to the geiieral linear equatioii of tlie iiiet1iotL g i w i i in the preceiliiig cliapter. Fiiially, Chapter S I 1 gives it treatnieiit of tlie h i i i i u l ni. first hy the ordinary niethotls aiill tlieli liy tlie tiietlioils of tlie 'This hook is iiot to l ~ erccoiiiiiicii(let1 to 011: \\-lie xishe:: quickly to acqnire clesterit>-iii the integration of eiluatioiis: for it is necessary to r e x i the firit fciur chaliters. almost half of the l)ool-onv \\-how interest ill tiint1iein:itics i D not cviifineel solel>. to its practical applicatioiis. 'rile firlt four cliiipters are especiall!- iiiterestiiig-,for the! have a continuit!. that is lacking iii other p:irts of the w r k . O t l l l l Snlr7-d
