August 14, 1884] 



NATURE 



359 



treated rather cursorily. In speaking of the man- 

 engine for raising and lowering men, Mr. Hunt points out 

 that the reason why this valuable invention is so little 

 used is " the unfortunate system under which the mines 

 of Cornwall and Devon are worked — a system which does 

 not encourage the holder of shares to take any interest in 

 the mines themselves, his interest being confined to the 

 market value of the shares which he holds." This remark 

 is unhappily applicable to other-districts. 



In Chapter IV., on ore-dressing, after an historical 

 sketch, the principles of the mechanical preparation of 

 ores for the smelter and the various kinds of machines 

 now in use are described with the aid of numerous illus- 

 trations. 



Chapter V., upon the discovery and extraction of iron 

 ores from veins and other deposits, is disappointing, on 

 account of its meagreness compared with the space de- 

 voted to less important metals, and the Cleveland ore 

 should scarcely have been dismissed in a dozen lines. 



Book IV. relates to the future prospects of British 

 mining. To persons interested in mines, whether as 

 owners, shareholders, workmen, or merchants furnishing 

 them with supplies, this book will no doubt seem the most 

 important in the volume. Mr. Hunt is not sanguine 

 about better prices for tin, and he says that " it is im- 

 probable that our native copper mines can be expected to 

 prove profitable for some time to come " ; in the case of 

 lead he evidently is not more hopeful, and though the 

 prospects as regards zinc are brighter, still we are unable 

 to supply our own wants. In spite of the productiveness 

 of our iron mines, we have to import more than three 

 million tons of iron ore annually. 



The fourth chapter of this book contains numerous 

 useful suggestions for working mines, and is well worthy 

 of consideration by miners and shareholders in mines. 

 With reference to profitable mining, Mr. Hunt says 

 (p. 868) : — " The question is frequently asked, Is British 

 mining a remunerative pursuit ? Various replies might 

 doubtless be given in accordance with any particular set 

 of views and opinions held on the subject, but mines pro- 

 moted by mere speculation can scarcely be expected to 

 become profitable, inasmuch as they are too frequently 

 grounded upon a misrepresentation of facts, while the 

 capital connected with them is often largely diverted to 

 the pockets of individuals whose main purpose is imme- 

 diate gain. Further, the management or conduct of 

 affairs is often leavened with ignorance and incompetency ; 

 the acquisition of personal gain, at the cost of unsuspect- 

 ing shareholders, being unfortunately sometimes the rule 

 of action." No one who knows anything about mining 

 can fail to indorse these remarks. 



In Chapter V., which contains the general summary 

 and conclusion, Mr. Hunt says that "the exhaustion of 

 our mineral wealth is now going onward at a rapidly in- 

 creasing rate," and the question arises whether we can 

 meet the demands of trade from British mines or not. 

 According to the author, our tin ore is practically inex- 

 haustible, but for copper, lead, zinc, and silver we must 

 depend greatly upon foreign and colonial mines ; of iron 

 ore we have enough for some years, though certain foreign 

 ores are of importance to us. 



The situation is summed up as follows : — " Without 

 great improvements in the principles of mining it will not 



be possible to work, at a profit, many of our deeper and 

 more extensive mines." 



The last two pages of the work, before the appendix, 

 contain several important maxims which deserve the 

 careful study of all persons engaged in mines, such as the 

 necessity of supplying pure air at any cost, of raising and 

 lowering the men by machinery, and providing for them 

 in the event of accident or disease. The concluding words 

 very properly strike at the rascality which has done much to 

 wreck British metal mining. " Beyond these, to enable the 

 adventurers in our Home Mines to compete satisfactorily 

 in the metal markets with the proprietors of colonial and 

 foreign mines, and to realise a profit on the sale of their 

 minerals, it is absolutely necessary to study the strictest 

 economy, and to establish — beyond the risk of any failure 

 — the highest principles of honesty in every department, 

 directly or indirectly, connected with British Mining." 



The size of Mr. Hunt's volume is apt to alarm the 

 reader, and the publishers would probably have done better 

 by issuing the work in separate books. It strikes us, too, 

 that undue prominence is given to tin, to the detriment 

 of the more important metal iron. From the " Mineral 

 Statistics" for 1883, we see that the iron ore raised had a 

 value of about 5 j millions sterling, whereas the value of 

 all the other metalliferous ores put together was only 

 \\ million. However, in spite of this favour shown to tin 

 and of occasional inaccuracies, Mr. Hunt's magnum opus 

 is very praiseworthy, as it contains a vast store of useful 

 information, and the antiquary, the miner, and the capi- 

 talist are greatly indebted to him for having taken the 

 trouble to chronicle so many valuable facts relating to 

 such an important branch of British industry as Metal 

 Mining. 



LETTERS TO THE EDITOR 

 [The Editor does not hold himself responsible for opinions expressed 

 by his correspondents. Neither can he undertake to return, 

 or to correspond with the writers of, rejected manuscripts. 

 No notice is taken of anonymous communications . 

 [The Editor urgently requests correspondents to keep their letters 

 as short as possible. The pressure on his space is so great 

 that it is impossible otherwise to insure the appearance even 

 of communications containing interesting and novel facts. ,] 



The International Geological Congress 

 Will you allow me to announce in your columns that, in 

 consequence of the outbreak of cholera in the South of Europe, 

 the International Geological Congress is postponed to September 

 1885. John McKenny Hughes 



Woodwardian Museum, Cambridge, August 12 



The Volcanic Dust Phenomena 

 I WOULD draw the attention of such of your readers as may be 

 travelling in Switzerland or other mountainous countries to the 

 circumstance that in the clear atmosphere of the mountains the 

 great corona or circle round the sun, as well as the semicircle 

 seen opposite the sun before and after sunset continue to be 

 markedly conspicuous ; and the higher one ascends the more 

 striking these phenomena are. I saw both the phenomena 

 especially remarkable on the Gornergrat, altitude 10,289 f ee '> on 

 the 21st and 22nd of last month ; and even as low as 4000 feet 

 they are decidedly more striking than at sea-level. It appears, 

 therefore, that the bulk of the volcanic dust, if such it be, that 

 still remains continues at a great elevation, and the prediction 

 made last autumn that it might remain for years in the atmo- 

 sphere, seems likely to be fulfilled. 



The explanation of the strange sunsets given by "F. A. R. R." 

 in Nature (p. 155), seems a good one, except as regards the 

 green appearance of the moon and stars ; I must confess I am 



