290 



NA TURE 



[July 



1895 



exhibited by the statement, on p. 11 1, that Rhea is ex- 

 clusively confined to the Chilian sub-ret;ion of South 

 America, especially after the author has stated on p. 20 

 that Rhea macrorhyncha occurs in Pernambuco and 

 Bahia. 



As likely to mislead the student, we must also call 

 attention to the so-called genera Aquias and Phyllotis 

 being placed among those characteristic of the Oriental 

 region, whereas Dr. Dobson,' whose views are en- 

 dorsed by Mr. Blanford, states that there is no justi- 

 fication for the separation of the forms thus named 

 from the ordinary Rhinolophiis. If the author has 

 reason to doubt the correctness of such generally ac- 

 cepted views, he should ha\e appended a note to that 

 effect. Many other points of this nature might be alluded 

 to ; but we cannot help regretting that the author has 

 once more resuscitated the myth of the fossil .Australian 

 elephant. 



While the book would have been much better had more 

 care been exercised on its composition and correction, it 

 will ser\-e a useful purpose as a general guide to the 

 principles of the geographical distribution of animals, and 

 may accordingly be recommended to the student, pro- 

 vided he have sufficient knowledge to steer clear of the 



pitfalls. 1^. l.M>KKKFR. 



ALKALI MANUFACTURE. 



A Tluoretical and Practical Treatise on the Manufacture 

 of Sulphuric Acid and Alkali,, ivith the Collateral 

 Branches. By George Lunge, Ph.D., Professor of 

 Technical Chemistrj- at the Federal Polytechnic 

 School, Zurich. Second edition, vol. ii. Pp. xi. 

 929. (London: Gumey and Jackson, 1895.) 



TO criticise, in the ordinary- sense of the term, such a 

 book as this, demands an experience as wide as that 

 of the author — not only in the laboratory investigation 

 and the exposition of the problems of chemical techno- 

 logy, but in the exigencies of daily life in a chemical works. 

 This dual experience is possessed by few, and the present 

 writer can lay n > claim to it. But the wide acceptance 

 of the first edition of Dr. Lunge's book as the work of 

 reference on alkali manufacture, makes the expression of a 

 judgment on its valu: superfluous, and the reviewer need 

 do little mare than make a general comparison between 

 the present volume and its predecessor of fifteen years ago. 

 It may at once be said that the book has been 

 thoroughly brought up to date. It is bulkier than the former 

 edition to the extent of over 2od pages, though many 

 processes described in detail in the earlier work, being 

 now obsolete, or nearly so, are here merely referred to ; 

 but though some of this increased bulk arises from lengthy 

 detailed accounts of new processes, yet most of it is due 

 to the small additions interpolated on almost every page 

 of the book. No published work on alkali manufacture 

 appears to have escaped Dr. Lunge, whether in journal 

 or patent literature ; and he has not only furnished an 

 admirable digest of the progress made in lc<hnf>l(>giral 

 thought and practice since 1880, but has throughout 

 given references to original sources. 



One change in arrangement commends itself at once : 



• " Cat. Otiruptcra llril, Mu».," p. 306. 



NO. 1343. VOL. 52] 



the modes of occurrence and properties of raw materials, 

 and products are collected in the first chapter, while 

 analytical methods are similarly gathered together in the- 

 second. .\ striking feature in the first chapter is the 

 amount of space devoted to native soda. Recent explora- 

 tions have greatly extended our knowledge 'of the occur-f 

 rence of this substance, and with sources of supply like 

 Owen's Lake in California, it seems not at all unlikely that 

 in a few years native soda may compete' on a large scale 

 with that manufactured by the Leblanc and the ammonia 

 processes. The chapter on analytical methods is very 

 complete, the chief new feature in it being • the dcscriptior 

 and illustration of Lunge and Marchlewski's gas analysis 

 apparatus on p. 113. It seems a pity that_those who buy 

 and sell alkali should not by this time ha\e reformed the 

 chaotic condition of " trade customs " which makes it neccs- 

 sar)' still to devote five pages of a work like this to the- 

 question of alkalimetric " degrees." 



In the chapter on the salt-cake process the changes 

 consist chiefly in the greater prominence gi\en to plus- 

 pressure furnaces, of which two forms are"figured, and to 

 mechanical furnaces. At the date of the first edition, plus- 

 pressure furnaces were in little more than an experi- 

 mental stage ; but the advantages they present have 

 gradually made themselves felt, and their use has become 

 correspondingly more frequent. The early type of the 

 Jones mechanical furnace has been omitted from this 

 edition, and mechanical furnaces are represented by the 

 later form of the Jones furn.acc, with fixed stirrers and 

 movable bottom, by the Mactcar furnace, and by Larkin's 

 mechanical roaster. These furnaces are all fully described 

 and figured, and the discussion of their merits .tnd 

 demerits is eminently fair. The account of the Hargreaves 

 process has been completely rewritten and greatly im- 

 proved, entirely new drawings of the arrangement of the 

 cylinders having been introduced. That this beautiful 

 process should not have further extended, is matter for 

 regret ; but, as Dr. Lunge justly says, it came too late — it 

 has had to succumb to the competition of the ammonia 

 soda process, and the consequent necessary subordination 

 of other considerations to the production, in the l.eblanc 

 process, of strong hydrochloric acid. 



The condensation of hydrochloric acid had reached 

 such a stage at the date of publication of the first 

 edition, that we find but few changes in this one, and but • 

 two noticeable additions : an account and discussion of 

 Dr. Murter's mathematical treatment of condensation, and 

 a description of the Lunge- Kohrmann |)late-C()!uinns. 

 The gist of Dr. Hurter's papers is, on the whole, very 

 faithfully reproduced : but there are two errors which are 

 likely to cause confusion to the reader unarciuainted with 

 the originals : on p. 308, lines 6 to 10, where the source 

 of the figure 43'3 is not obvious, the fact being that it is 

 quoted from a third example of Hurler's, in which the gas 

 dealt with contains 43-3 per cent, of hydrochloric acid ; 

 and on p. 313, where, in converting Dr. Hurter's Knglish 

 measures into metric units, 20 cubic feet per second is 

 taken as 20 feet per second, and the resulting contact 

 figure is worked out to 324 instead of 3474. The Lunge 

 towers arc described in the body "f the work, and details 

 of their structure, as well as a summary of results obtained 

 in their actual working at Duisburg, are given in the 

 addenda. These figures are certainly remarkable tcsti- 





ifc 



