t h a t there was something in the mercury besides ammonia and hydrogen, p. 83. On the other hand the author is \Tilling to believe in the existence of t h e imaginary substances, CuAl and Cu,rll, p. 15j. I n the chapter on the physical cause and nature of valency, the follon.ing paragraphs, p, 167, seem worth quoting: " I t is well known t h a t the numerical values of the valencies of those elements which exhibit variable valency usuaily differ by two, or multiples of t w o units. Thus gold is mono- and tri-valent. Sitrogen and phosphorus are triand penta-valent. Sulphur is di-, tetra-, and hexa-valent. So long as the old ideas prevailed, that the atoms were provided with hooks and eyes, which represented their valencies, a physical interpretation of the above v-as clear, B u t the demolition of these crude notions has rendered the explanation of multivalency more difficult. "The suggestion of Barlon. and Pope is, to say the least, very ingenious. Imagine a n assemblage of close-packed spheres, and let one of these spheres have a valency volume m. If this is removed, and into the cavity thus produced a sphere of \-olume vi - I is pushed, i t will be clear t h a t a second sphere, of valency volume I , must simultaneously be introduced into the enveloping shell of atoms, if the close-packing is to be restored without remarshalling. This is obviously equivalent to the insertion of an atom of valency I in the space already occupied b y a n atom of valency m,and the filling of the gap t h u s produced in the enveloping shell by the insertion of a second atom of valency. I. The atom of valency i n will thus function as an atom of valency in i2 . Similarly, b y pushing two atoms of valency I , or \That conies to the same thing, an atom of valency 2 , into the space already filled by a n atom of valency )n either t x o atonis of valency I . or one of valency 2 , must be inserted into t h e enveloping shell. Consequently the atom originally exhibiting a valency tn, now functions a s a n atom of valency v i 1. Sulphur is a case in point. " I t has already been pointed out, however, that all atonis exhibiting the same valency have not exactly the same valency volumes. For example, as a n y vertical column in the Periodic Classification is descended, a slight change in volume is exhibited, nltliough it is not sufficient to change the valency by a whole unit. If, therefore, atoms of valencyvolume exactly equal to unity are combined ivith other atoms of \-alency-\-olume intermediate between t w o whole members, i t is clear t h a t various assemblages may be formed. in which the numbers of monuvalent atoms attached to one of the polyvalent atoms will not always difier b y two. Llolybdenum is a good example of this, for the di-, tri-. tetra-. and penta-chlorides. JIoCI,, JIoCI,, JIoCI,, and LloC15, respectively, are known." The author had a good subject and he has written a useful hook; b u t t h a t is all t h a t he has done. The I~ool;is merely one of the series and nothing more. 1 I .ildcr D , Uaiiwojf.
+
MCthodes de CalorimCtrie. Crifhcs nu Lnboratol'w Therwiique de l'L.)zzuersitd tic .lioscou p a r I T . Loi~qu2'1~I'?zc ct A , S c i i u k a r e ~ . Tmdirit d e la Russc pur G. T c v Gazariail. 18 X 27 c m ; pp. 192. Paris: A. Hermaim. Gerzix: Georq Co., 1908. Price: Liiicn, 8 jravcs.--Ostensibly this is merely a book describing the methods of calorimetry in use a t the Xoscow laboratory b u t actually
S e w Books
419
i t is a good deal more than t h a t . IYhen giving reasons for using this, that, or the other method, it is of course necessary to discuss general principles to a certain extent. I t is distinctly interesting to learn t h a t the Germans use thermometers xvith milk-glass scales because they are unable to make such a glass t h a t the zero of the thermometer will be fairly constant and t h a t will permit the ruling of fine lines. Although arranged a s a book, the volume really is a series of essays b y one or the other of the authors. There are fourteen of these essays or chapters and the? are well worth reading though the reviewer feels t h a t the effectiveness of the book would have been increased if there had been less doubt \vhether the subdivisions v e r e essavs or chapters. IT.zlde,. u. Ua11crvjt The Chemical Constitution of the Proteins. B j , R. H . ddi7i.s Pliiiziiio.. .lioJiogvaplis oii Biocliemistrj. Edited b j , R. 13. d d e r s Plimnier ai1J F . G. Hopkiiis. Part I . ~jX 24 cm; p p . xii - 100. Price: Si.00 iiet Port I I . 15 X 24 c w ; p p . i i i i - 6 6 . Price: So.80 ? i d . - 1 - e ~i - o r k : L o ~ i g i i i ~ i i sG, ~ . L K ~ L E? Co., rgo8,-In the preface the author says: “The substance Protein, Tvhich constitutes the most important p a r t of the material basis of 311 anirnd and vegetable life, has naturally attracted the attention and energ>- of numerous investigators throughout the past century. Progress in the study of this subject, on account of its difficulty, has been exceedingly slow, and i t is only of recent years t h a t the discovery of new methods b y Emil Fischer has enabled u s to increase our knowledge to its present extent. By these methods we hax-e been able to advance from the conception of “albumin” to its actual separation into numerous units, and also to determine their arrangement in the molecule. On this account a monograph embodying the results of the most recent investigations, together with their connections with the work of the other and earlier investigators, needs no excuse for its appearance, a s the subject is now being studied in every direction.” I n the first volume tvhich treats of the chemical composition of the protein molecule and the chemical constitution of its units, the subject is taken up under t h e headings: the monoamino acids ; the diamino acids; monoamino-monocarboxylic acids ; monoamino-dicarboxylic acids ; diamino-monocarboxylic acids ; heterocyclic compounds ; the optically active amino acids, The second volume treats of the synthesis of the proteins and the headings are: the condensation together of amino acids; the biuret base; the linking together of amino acids; the polypeptides. Each volume has its on-nbibliography and the two give a satisfactory and useful outline of this important subject. T T-ildrr D . Bnizcvojt The Chemisty and Literature of Beryllium. B y Cizarlcs Latizrop P a r s o ~ i s . CVL; p p . iz. 180. Eastoiz: Chimicul Pzthlisiiiiig Co., Ip09.-In the preface, the author says: “This book is w i t t e n with the main oliject in vien. of saving preliminary study and labor to future investigators of beryllium and t o point out some of the peculiarities of this interesting element which are a p t t o lead the nol-itiate toward erroneous conclusions. Especially is i t desired to call attention to the fact that a large proportion of its credited compounds are in reality but indefinite solid solutions. This condition of the literature of beryllium is due to the abnormal extent to which its hydroxide is soluhle in
14 X z z
+
