Ug. 12, 1875J 



NATURE 



293 



zealously supported in the extensive plans of obsei-vation 

 arranged by him, by the other officers of the establish- 

 ment. The great comet of 1874 was followed with the 

 large refractor of the Argentine Observatory (which, Dr. 

 Gould informs us, is an ii-inch by Fitz, of New York) 

 until the i8th of October, the comet having been first 

 seen there, in the morning twilight on July 27 ; at the 

 last observation it was within about 12° of the South Pole. 

 [Our last remarks on this comet should have been headed 

 Comet, 1874(111,)]. 



THE LATE W. J. HENWOOD, F.R.S. 



THIS distinguished mining geologist, who died at 

 Penzance last week, in his seventy-first year, was 

 originally a clerk in the employment of Messrs. Fox, of 

 Falmouth, to whose counsel he was considerably indebted 

 in his early scientific work. By very great industry and 

 careful observation he acquired an unsurpassed knowledge 

 of the mineral deposits of Cornwall and Devon, and after 

 fulfiUing a succession of important mining appointments, 

 he became Assay Master of tin to the Duchy of Cornwall. 

 This post being abolished, Mr. Henwood's great expe- 

 rience was utilised in -reporting upon and developing a 

 number of mining districts in South America, Canada. 

 &c. ; and after the cessation of his travels, he lived at 

 Penzance in comparative retirement. His great works 

 are the fifth and eighth volumes of the " Transactions of 

 the Royal Geological Society of Cornwall," devoted respec- 

 tively to the metalliferous deposits of Cornwall and Devon, 

 and to those of the foreign countries he had visited. But 

 his scientific writings, besides these, were very numerous ; 

 a list of them occupies seven columns in the " Bibliotheca 

 Cornubiensis." 



As a scientific man Mr. Henwood was characterised by 

 indefatigable labour, great caution, love of accuracy, and 

 moderation of expression. In his publications he scarcely 

 ever mentions a fact of any kind which had not come 

 under his own experience, without giving the authority for 

 it. Thus many of his writings are marvels of copious 

 reference. He persisted in doing everything with this 

 extraordinary amount of labour and care up to the last, 

 notwithstanding that he suffered for many years from a 

 very painful heart-disease. His scientific work ceased 

 only with his death. So long as he could sustain even an 

 hour's intellectual effort during the day, that was devoted 

 to the arrangement of his stores of facts and observations. 

 I beheve that scarcely one of his cherished objects in this 

 respect remains unfulfilled. 



Mr. Henwood's address to the Royal Institution of 

 Cornwall in 1871, extending, with references, to sixty-five 

 pages, affords ample evidence of the value of his observa- 

 tions and of his scientific ability. It includes the most 

 admirable and complete compendious account of the 

 mode of occurrence of metalliferous deposits in Cornwall 

 which has yet appeared, and is characterised by that 

 absence of theoretical assumption which specially marked 

 him as an observer. The orderly arrangement of accu- 

 rately-observed facts was his object ; theorising he had 

 little affection for ; suspended judgment on unproved 

 theories was his consistent attitude. 



In personal character Mr. Henwood won the high 

 regard of all who knew him intimately. His acquaint- 

 ance with men and manners was so great and varied, 

 his memory so retentive, and his conversational style 

 so simple and lucid, that to talk with him was one 

 of the most delightful and instructive of intellectual 

 recreations. His estimate of his own labours and merits 

 was unaffectedly modest, althguah he would resist, if 

 possible, any unfair representation of his work. 



In the spring of the npresent year the Murchison 

 Medal of the Geological Society was awarded to Mr. 

 Henwood. An extract from a letter written by him to a 

 friend on this subject may fitly close this notice : " Mr, 



Evans's far too flattering estimate of my poor labours was 

 most kindly intended. Although the distinction cannot 

 but afford me pleasure, this is as nothing compared with 

 the kind, and even affectionate, congratulations of your- 

 self and my other friends. All these I carefully preserve, 

 as they will show what I have done far better (though in 

 an undeservedly favourable light) than the mere official 

 record." G. T. Bettany 



THE INTERNATIONAL CONGRESS AND 

 EXHIBITION OF GEOGRAPHY 



'T^HE Geographical Exhibition continues to have in- 

 ^ creasing success, although the price of admission 

 has been raised, except for schools, for which the original 

 price, a penny a head, has been kept, and the galleries 

 are crowded with children under the guidance of their 

 teachers. It is said that all the soldiers of the garrison 

 of Paris will be marched through the galleries under 

 the guidance of their officers, when the Congress is 

 over. The Exhibition will be prolonged to the end of 

 the month. 



Several improvements have been made in the English 

 section since our last notice. Examples of the several 

 maps published by the Ordnance Survey have been exhi- 

 bited from an inch to ten feet per mile. Although com- 

 pleted only at a late p>eriod, the exhibition of the Geological 

 Survey of Great Britain has been very successful ; an 

 immense number of maps have been exhibited, and arc 

 said to be the finest in the whole exhibition building. We 

 might refer to a number of other exhibits honourable to 

 Enghsh enterprise, but we must confess that Russia has 

 carried the day, not on account of her private enterprise, 

 but in consequence of the strenuous action of the Govern- 

 ment. It is very likely that St. Petersburg will be chosen 

 by common consent for the seat of the next geographical 

 exhibition. 



M. Gloesener, member of the Royal Academy of 

 Sciences of Belgium, exhibits a chronograph available for 

 registering the flight of projectiles as well as for recording 

 astronomical observations for the determination of longi- 

 tude. The cylinder can be put into rotation at the rate of 

 four turns in a second or one turn in thirty seconds, accord- 

 ing to the order of phenomena. It requires only the 

 power of Daniell cells and ordinary magnet needles, with- 

 out any electrical spark. It is very cheap, compact, and 

 easy to set in operation. 



The Ryssclberghe self-registering meteorograph has 

 been admitted, as we have already noticed, to supersede 

 any similar instrument in existence. Copper plates 

 engraved automatically can be used in printing, having 

 turned into relief by the processes already described. 



M. Lynstrom, of the University of Helsingfors, has sent 

 to the Geographical Exhibition an interesting instrument 

 invented by him to demonstrate that auroroe are pro- 

 duced by electrical currents passing through the atmo- 

 sphere in the polar regions. The apparatus is put daily 

 into operation by M. Mohn, the director of the Meteoro- 

 logical service of Sweden, and it was constructed at the 

 expense of Mr. Oscar Dickson, the Gottenburg mer- 

 chant, who has fitted out the Swedish Polar Expedition 

 under Prof. Nordenskiold. Our illustration will give an 

 idea of the apparatus. 



A is an electrical machine, the negative pole being 

 connected wtih a copper sphere and the positive with the 

 earth. 



S s' are of ebonite as well as RR tiei, so that B is quite 

 isolated as the earth in the space. B is surrounded by the 

 atmosphere, a' n' a' a' a' a' are a series of Geissler tubes 

 with copper ends above and below. All the upper 

 ends are connected with a wire which goes to the earth, 

 consequently a current runs in the direction of the arrows 

 through the air, and the Geissler tubes become luminous 

 when the electrical machine is set into operation, 



