416 



NA TURE 



[March 5, 1885 



ticular cartridge depends upon its own power to withdraw 

 itself from the barrel, it will be obvious that the cartridge 

 cannot remove itself from the barrel before it explodes. 



A gun which loads and fires itself is certainly a novelty, 

 and presents many interesting features and possibilities 

 to any one who takes an interest in implements of war 

 fare. 



The gun may be trained in any direction by turning the 

 crank which operates a tangent screw, the stem of which 

 projects from the platform immediately below the cartridge 

 box seen on the top of the tripod, whilst a fine adjustment 

 in elevating may be obtained by turning the small hand 

 wheel, which forms a part of the diagonal telescopic brace 

 which supports the rear of the gun. By loosening the 

 three-handled screw immediately below the central 

 standard, the gun may be turned completely round, and 

 by loosening the thumb screw of the telescopic brace, the 

 gun is absolutely free to be moved up or down or in any 

 direction while firing. If, however, it is desired to have 

 a definite stop to the horizontal play of the gun, as, for 

 instance, when firing upon a bridge, a pass, or a ford, or 

 upon earthworks, the gun may be sighted between the 

 two points, and adjusted by the thumb nuts on the tangent 

 screw stem, when the gun will be free to operate between 

 these two points, but will not go beyond them. Fig. I is 

 a perspective view of the gun. Fig. 2 is a longitudinal 

 central section of the weapon. A is the block or bolt 

 which slides freely after the manner of the cross head of 

 a steam-engine ; b is the barrel ; c the locking device for 

 securing the block to the barrel at the instance of dis- 

 charge ; D is the cocking lever ; E, the carrier which 

 draws the cartridges out of the belt and deposits them in 

 the feed wheel G ; F is the belt wheel which draws the 

 belt of cartridges into the gun ; H is a connecting rod 

 made slightly elastic by being provided with a strong 

 spring ; I is a crank which does not, however, turn com- 

 pletely round ; L is a point of resistance, against which 

 the cocking-lever, D, strikes at each rearward motion of 

 the block ; k is a shaft connected with the trigger, which 

 operates upon the sear and also upon the controlling 

 chamber J ; M is the extractor which starts the cartridge 

 from the barrel ; N is a bar which holds the locking 

 device C in position, and which raises it or unlocks it at 

 each rearward motion of the barrel ; O is a casing sur- 

 rounding the barrel, which may be used, if desired, as a 

 water jacket. 



RORAIMA 



OUR readers will be interested in reading the following 

 letter, which has just been received at Kew, from 

 Mr. im Thurn, in confirmation of his telegram already 

 published (Nature, vol. xxxi. p. 342), announcing his 

 successful ascent of Roraima : — 



Georgetown, February 4, 1 885 

 I have just sent a most brief telegram (such things are 

 expensive here) which will, I hope, give the first news 

 that Roraima has been ascended ; and I much wish I 

 could write even a brief report to go by this mail, but 

 ever since I have been back (we got back four days ago) 

 I have been in bed with the most severe attack of fever 

 and ague that ever befel me, and, though the doctor 

 assures me that I have now turned the corner, I am so 

 weak as to be quite unable to sit up. However, before 

 next mail I must manage something. And in the mean- 

 time I send a local paper which purports to give an 

 account of the expedition derived from myself. The main 

 facts are tolerably correct, but the details are much 

 blurred. 



We were quite successful in getting to the top, and 

 have found that the plateau is by no means the isolated 

 spot it has sometimes been supposed to be. It was, 

 however, a great disappointment that, our way up being 



so extremely laborious, it would be quite impossible, with- 

 out a very large expenditure in somewhat smoothing the 

 path, to carry up hammocks, &c, provisions, and firewood 

 (for there are no trees on the top and it is bitterly cold) — 

 it was a great disappointment, I say, that we could only 

 explore the top for a short distance from the point which 

 we first reached. I see, however, no reason to believe but 

 that the whole top is of one character. The scenery 

 is in the highest degree wonderful. I made many fairly 

 successful sketches (considering I am no artist), which 

 will give a very fair idea of the mountain and of the 

 scenery on the top. As I wish to keep the original 

 sketches for the present, to copy them at my leisure, I 

 have just handed the half-dozen most characteristic 

 amongst them to a photographer here, who has before 

 been fairly successful in copying drawings for me, and I 

 hope to send you copies by next mail. The vegetation 

 (on the top) is most wonderful, but somewhat scanty and 

 quite dwarf. I have between 300 and 400 species for 

 you. I have also some living plants {HeHampliora, three 

 most exquisite Utricularias, two of which are, I fancy, 

 new ; and a few other things), but, as these want much 

 nursing, I have put them into wardian cases, and shall 

 take them home for the present. (I miss jenman now, 

 and have throughout the expedition, immensely.) 

 Yours very truly, 

 (Signed) Everard F. im Thurn 



NOTES 



At the moment of going to press we have received from Sir 

 E. J. Reed a communication protesting against some of the state- 

 ments made in our article last week on " The Relative Efficiency 

 of War-Ships," and pointing out that the system of construction 

 advocated by him was greatly modified during the ships' pro- 

 gress. So far from wishing to deal unfairly with Sir E. J. 

 Reed's views, one of our chief objects was to support his protest 

 against the existing state of things, by suggesting that scientific 

 experiments should be resorted to to settle some of the questions 

 on which doubts have been expressed by contending authorities. 



We regret to learn that M. Milne-Edwards is lying in a 

 precarious condition. 



Our readers will regret to learn that Prof. Bonney will resign 

 his post as secretary of the British Association after the Aberdeen 

 meeting. Prof. Bonney, we believe, feels compelled to take 

 this step mainly on account of the inroads which the work of the 

 Association makes upon his time. No one will regret his retire- 

 ment more than the council and his fellow officials. 



M. Bouquet de la Grye has received a mission from the 

 French Minister of Public Instruction to proceed to Teneriffe in 

 order to study the variations of gravitation according to altitude. 

 We have received from the Royal Society of Public Medicine 

 of Belgium its recent monthly tables. With the present year it 

 assumes a new field of usefulness. Founded originally in 1876, 

 it was composed of men who by their position or special know- 

 ledge were able to participate (I) in determining the cause of 

 mortality in general, and the circumstances which affect public 

 health ; (2) in informing and assisting the authorities by special 

 studies and researches ; (3) in preparing the medical topography 

 of Belgium ; and (4) in discussing at annual public meetings 

 questions presently relating to this work. The Society is formed 

 of eleven local subdivisions, each sending a number of members 

 to form the general council. But in addition to these sub- 

 divisions, for administrative purposes, the Society is also divided 

 for the scientific service into a number of zones limited according 

 to the physical nature of the districts. The medical topography 

 i of the kingdom, and all questions relating to it, are studied 

 I according to these zones. During last year the Society made a 



