640 



NATURE 



[Oct. 31, 1889 



is still such that the teacher has to assume an entire 

 ignorance of even the most elementary facts of physical 

 science. The students at the Royal Naval College are 

 no doubt largely recruited from the public schools. Any 

 well-devised scheme of school instruction ought, one 

 would think, to give them such a knowledge of the rudi- 

 ments of chemistry as to obviate the necessity for the 

 teacher to spend a considerable fraction of the limited 

 time at his disposal in discussing such matters as 

 nomenclature and notation, formulae and equations, the 

 simple laws of chemical combination, effects of tempera- 

 ture and pressure on gases, and so on. But Prof. Lewes 

 no doubt, as indeed his book demonstrates, finds it 

 absolutely necessary to deal with these preliminary 

 matters in the outset of his course. Hence the book 

 naturally divides itself into two portions — one, and of 

 course the most important portion, treating of the tech- 

 nical relations of chemistry to the work of the services ; 

 and the other treating of such of the general principles of 

 the science as are necessary to an intelligent appreciation 

 of these relations. The latter portion, of course, precedes 

 the former in the actual plan of the book. 



It is, however, characteristic of the eminently practical 

 character of the book that Prof. Lewes loses no opportunity 

 of pointing the moral by some reference to a " service " 

 fact. Thus he has occasion to treat of the chemistry of the 

 galvanic battery, and what he has to say about the electro- 

 chemical behaviour of metals leads up to the question of 

 the fouling of ships' bottoms ; the possibility of strong 

 galvanic action set up in iron ships causing the destruc- 

 tion of the screw shafting and rudder-posts, &c. ; the effect 

 of mooring a copper-bottomed vessel to an iron pier, &c. 

 No officer intelligently following a course of instruction 

 such as this can be blind to the influence which science is 

 capable of exerting on the worli of his profession. The 

 sailor whose respect for a fluid which is so useful in 

 navigation is so profound as to forbid him to drink of it, 

 would doubtless have that respect intensified by the account 

 which Prof. Lewes gives of the physical and chemical 

 characters of water, although, possibly, the section on 

 filters and filtering media may have only an abstract 

 interest for him. This chapter, of course, contains no- 

 thing but what is the common property of text-books ; 

 but it is put together in such a manner as to show 

 the bearing of the facts on the every-day life and work 

 of the sailor. The chapters on Boiler Incrustation and 

 on Ventilation are also capital illustrations of the way 

 in which the service aspects of the matter are dealt 

 with throughout the book. A short account of carbon, its 

 oxides, and simplest hydrides, naturally leads up to a de- 

 scription of the manufacture of coal-gas, the nature of 

 luminous flames, the causes of fire-damp explosions 

 both in the mine and in the holds of vessels ; whilst the 

 chapter on fuel is of especial interest, from the manner m 

 which the results obtained by the Commission on the 

 Navy coal, and the reports as to the value of liquid 

 fuels, are summarized and discussed. The methods of 

 calculating the evaporative value of fuel from percentage 

 composition, and the mode in which such calculations 

 are checked by calorimetric determinations, are also 

 described, and their precise value indicated. The subject 

 of Explos'ves naturally takes up a considerable space. 

 The mode of manufacture of service powders, cocoa 



powders, amide powder, &c., is fully described and 

 illustrated, and the nature of the chemical changes on 

 firing gunpowder, as determined by Noble and Abel, 

 Lenck, Karolyi, Bunsen, and Schischkoff, is explained in 

 detail. The chapters have indeed been put together with 

 special care, and contain much that has not yet been 

 incorporated with any other text-book, not only as to 

 details of manufacture, composition, and mode of decom- 

 position, but also as regards proving and keeping. This 

 question of the effects of storing in overheated and badly 

 ventilated magazines is extremely important, especially in 

 regard to powders for large ordnance, and the little that 

 is at present known on the subject is stated in the book. 



Only such compounds of the metals and non-metals 

 are dealt with as have immediate relation to service 

 questions. In treating of the action of light upon silver 

 salts the author gives a concise account of the more im- 

 portant methods of photography with special reference to 

 dry-plate work ; and the book concludes with a chapter on 

 the chemical nature of the more generally used inorganic 

 pigments, and on the causes of corrosion and fouling of 

 ships' bottoms and marine boilers. This constitutes one of 

 the most valuable sections of the work, and embodies the 

 results of much reading and original investigation. 



We congratulate Prof. Lewes on having compiled a 

 most useful and eminently practical work. It of course 

 makes no pretensions to be a complete manual of 

 inorganic chemistry, but it seeks to deal in the most 

 direct manner with those ma-tters which are of special 

 interest to the class of readers for which it is specially 

 intended. It is capitally printed, and for an English 

 text-book, unusually well illustrated ; indeed, the entire 

 "get up" of the work reflects great credic on the 

 publishers. The book is, on the whole, well up to date, 

 and every care has apparently been taken to verify state- 

 ments of numbers and constants. The mode of decom- 

 position of potassium chlorate given on p. 66 should, 

 however, be amended in view of the work of Teed, and 

 of Frankland and Dingwall ; and the statement as to the 

 action of peroxide of manganese in facilitating the break- 

 ing up of the chlorate requires alteration. It may also be 

 pointed out, in view of the passage on p. 70, that oxygen 

 compounds of fluorine are known, e.g. the oxyfluoride of 

 phosphorus. Chlorine also has been solidified, and the 

 statements as to the boiling and melting points of bromine 

 and iodine given on pp. 315, 317, and 320 are conflicting. 

 The figure on p. 379 is hardly a sufficiently accurate re- 

 presentation of a puddling furnace. However, these are 

 but minor blemishes that can readily be rectified in the 

 second edition which we trust may be speedily called for. 



WATTS' DICTIONARY OF CHEMISTRY. 

 Watts' Dictionary of Chemistry. Revised and entirely 

 rewritten, by M. M. Pattison Muir, Fellow of Caius 

 College, Cambridge, and H. Foster Morley, Professor 

 of Chemistry at Queen's College, London. Vol. II. 

 (London : Longmans, Green, and Co., 1889.) 



THE appearance of the second volume of the new 

 edition of " Watts' Dictionary " will be welcomed, 

 not only by chemists of every persuasion, but by all who 

 love and work at science. This volume, reaching from 



