7nnns, Greoi & Co., 3028. Tlic J l C w edition of h o f , Fiiidlny's instruct.irc book cont.nins n consitlcrnblc nmount of ncw mnttcr. ~Iiilt~i-co~iipo~ic~it systcnis 11n\*c rcccivccl furtlicr attention, nnd the scction on iron-carbon nllo>.s hns bccn rcvisccl for ~,IIC ficconil, but not,, wc S I I S ~C C ~, for thc Inst, timc. Thc sections on sulpltur and pliospliorus hnvc bccn rcwrit tcn, ant1 nn intcrcst,ing stud>* lins bccn included of thc condition7 of form n 1' 1011 of cnlciuni alunii~iiiiin silicates. 'J~licsc add i t i o i ~ ~indoubtctll~ incrcnsc t.Iic vnluc of t.11~ book. TIic nppcnrnncc of fifth cdition of n tcstbook of t.liis nnturc in i t d f rciidcrs unncccssary tlic prnisc of a rc-icwcr, and discounts his criticisnis. Yet ~icrlinps n fcw gciicrnl rcruarlis may iiot bc out, of ~I R C C , froin oiic wlio rcnicnibcrs, as a studciit,, rcnding tho first cdit.ion nit,li grcnt iiitcrcst. niid p1c;isiirc. Profcssor Fhicllny's book is n gcncrnl introduction to tlic study of 1wtcrogcncous clicniicnl cquilibrin. Tlic plinsc rulc iq only onc of tlic guiding principles whicli can bc brouglit to bcar on such problcins. It is, itself, a gcncrnlimtion of coiiiinonscnsc pinciplcs wliieli wcrc npplicd to spccific problcins long bcforc thc plinsc rulc was cnu~icintcd. For so11112 rcason, difficult to npprccinte nftcr tlic Iiipsc of ;'cars, its tliscowrcr succcrdcd in conccnling this siiiiply d c r i ~i b l c rulc in n forcst of 111iitllc.nint,ics. 1t.s siibscqurnt rcscuc niid ntloption by Roozcboozn Iind, tlicrcfore, n cci.tnhi clcni~iit. of roniancc ; and the roinniicc Iias suct~ccclrtl in clinging to this (lay. l'lic plinsc rulc is still " trotted out '' ns n Itind of iiifnnt prodigy ;