Jan. 3, 1889] 



NATURE 



22 



A^ 



receive a negative answer ; and as a matter of course the 

 man of science is, therefore, unable to be dogmatic or to 

 train a necessity : he cannot clearly recognize, on a 

 not proven " verdict, the duty of wounding the extremely 

 sensitive feelings of millions of his fellow-men, on a sub- 

 ject that is amongst the most tender of all that pertains 

 ' to humanity. 



Our idea is that in the current state of public opinion, 

 and in the current state of scientific knowledge, it is best 

 to let the public feeling towards cremation work its own 

 way, and to let earth-to-earth burial also have its free 

 course. 



Cremation will come partly by necessity, partly by a 

 radual sentiment in its favour. To force it by conjuring 

 .;i dangers which do not exist is the very means of arrest- 

 ing it in its progress. We do not say that the work we 

 have had under review is open to too severe criticism on 

 these grounds ; on the contrary, it adduces such a number 

 of sound arguments in support of its case, and, on the 

 whole, shows such a just and good weight on its own side, 

 that we commend it as an excellent treati.-^e— we should 

 not improperly say standard treatise — on cremation. 



ASS A YING. 

 Practical Metallurgy and Assaying: a Text-book for the 

 use of Teachers, Studettts, and Assayers. By Arthur H. 

 Hiorns. Pp. 471, with 91 Illustrations, Appendix, and 

 Index. (London : Macmillan and Co., 1888.) 

 SSAYING was a term originally used to denote the 

 estimation, by the agency of heat, of a particular 

 metal in an ore, alloy, or other metallic compound. Since 

 the publication of Agricola's work in 1556, numerous 

 English translations of foreign treatises on the subject 

 have been published. Amongst these may be mentioned 

 the translations of the works of Erker (1629), Barba (1674), 

 and Cramer (1774). Assaying by the dry way has changed 

 so little that the methods and instruments described in 

 these old books might still be successfully used. Since 

 the introduction, however, of the rapid and accurate wet 

 processes, improvements have quickly followed each 

 other, and from a particular ore a larger yield is now 

 obtained than was formerly the case, so that the dry 

 methods are, with a few exceptions, rapidly falling into 

 disuse, as in many cases they do not indicate with suffi- 

 cient precision the amount of metal actually present in 

 the ore. The modern English literature of assaying is 

 confined to Mitchell's large treatise, and to the chapters 

 given in Percy's works and in Phillips's " Elements of 

 Metallurgy." No small text-book, in which full cognizance 

 ; is taken of wet processes, has hitherto been published^ 

 and a gap in our metallurgical literature has now been 

 well filled by Mr. Hiorns's useful book, which is based on 

 the course of mstruction organized at the Royal School 

 of Mines by Prof W. C. Roberts-Austen, to whom the 

 author, as an old pupil, dedicates his work. In all the 

 Continental Schools of Mines, the instruction is con- 

 ducted in a most unsatisfactory manner. Large classes 

 rapidly pass through the various assaying processes, all 

 the students working together with military precision at the 

 Professor's word of command. In London, on the oiher 

 hand, each student works independently, and is not per- 

 mitted to pass from one metal to another until he can 

 prove that he is able to constantly produce trustworthy 



results. As a student of the Royal School of Mines, Mr. 

 Hiorns has thus had an excellent training for the task he 

 has undertaken. Besides this, as Principal of the School 

 of Metallurgy at the Birmingham and Midland Insti- 

 tute, he has had ample opportunity of ascertaining the 

 wants of the average student. 



Like so many of the text-books of science now pub- 

 lished, Mr. Hiorns's book has been arranged to meet the 

 requirements of the Science and Art Department Syllabus. 

 The first part contains a number of experiments for the 

 student to perform in order to elucidate the principles 

 upon which metallurgy is based ; the second part con- 

 tains an account of the methods of assaying by dry 

 methods ; whilst the third deals with assaying by wet 

 methods, and includes volumetric analysis and the 

 analysis of furnace gases. The course is very systema- 

 tically arranged, and it is certain that any student who 

 has performed the experiments enumerated would be 

 thoroughly well grounded in practical metallurgy. And 

 the fact that such a book is now required by a large num- 

 ber of students in evening classes shows what excellent 

 service the Science and Art Department is doing for 

 practical metallurgy throughout the country. 



The author discusses several of the newer methods, 

 such as Turner's method of estimating carbon in iron, 

 and alludes to recent researches, such as those of Beringer 

 on the accuracy of the volumetric estimation of copper. 

 He appears, however, to be unacquainted with the newer 

 methods in use on the Continent, and it is to be regretted 

 that he has not consulted the standard works of Balling 

 and of Bruno Kerl, or the careful abstracts of foreign 

 papers published in the Journals of the Chemical Society 

 and of the Iron and Steel Institute. It is to be regretted, 

 too, that there is a want of uniformity in the weights and 

 measures adopted. Grains and grammes, ounces and 

 cubic centimetres, are used indiscriminately. For indus- 

 trial purposes, it was perhaps necessary that the '-grains" 

 should be retained. But, with regard to the "ounces," many 

 assayers, who are familiar with metric measures, have no 

 idea how many ounces make a pint. In the nomencla- 

 ture and notation, there is also an unfortunate want of 

 uniformity, as is shown by the indiscriminate use of the 

 terms, oil of vitriol and sulphuric acid, carbonate of soda 

 and sodium carbonate, haematite and hematite, OH, and 

 H4O, SO4H2 and H.2SO4. The book is remarkably free 

 from typographical errors. The name Fresenius is, 

 however, spelt wrong in places (pp. 174, 183) and " oxide 

 of silica" (p. 312) is a compound unknown to the chemist. 



On the whole, the work is an excellent one, and will, no 

 doubt, prove of great service to the teachers and students 

 of classes in practical metallurgy. Chemists generally, 

 accustomed to ordinary laboratory manipulation, will be 

 interested to see how many operations there are, which, 

 while differing from those with which they deal, are 

 capable of affording very trustworthy results. The illus- 

 trations are of a very effective character, and are well 

 executed from drawings that have been prepared with an 

 amount of care not usual in figures of this class. Mr. 

 Hiorns's literary style is far from faultless, but his instruc- 

 tions are always perfectly clear, and, to use the words of 

 an old metallurgist, " he writes like one who hath black'd 

 his Fingers and sing'dhis Beard in metallick Operations." 



B. H. B. 



