328 



NATURE 



\Ang. 2 2, 1S72 



dangproiis or explosive. The principle of the lamp i"; 

 based on the fact that when a mixture of any inflammable 

 gas or vapour, with air in explosive proportions, is lighted 

 ontlesurfare of wire gauze, havini; meshes sufficiently 

 small to I re> ent the passage of flame, and a suitat>le tub.- 

 or chimrey is placed above, so as to prevent admission 10 

 the chimney except through the wire gauze, a musical 

 sound is produced varying in pitch with the size of the 

 flame and dimensions of the chimney. 



A number of intcr-sting experiments were exhibited to 

 illustrate this principle, and various minr-r's lamps as con- 

 structed were exhibited and tested in mixtures of air with 

 ordinrry coal ga^, when they at once indicated the danger 

 as soon as the atmosphere by which they were surrounded 

 contained suffiiient gas to be dangerous, bv emitting a 

 ftrong clear sound like that of a horn, whirh could be 

 heard at a considerable distance. Another form ol this 

 lamp was also shown, intended to he employed as a 

 stationary warning apparatus or alarum af'er being placed 

 in any part of the mine considered hkely to ensure the 

 sa^etv of the workmen, so that it migt^t sound the danger 

 signal before the air around it was so far charged with fire- 

 damp as to become explosive. The nmeltv and impottance 

 of such an invention were apparent to an aumence of 

 practical men ; and besides p issing a cordial vote rf thanks 

 to the inventor, arran(;emeiits were made for at once fully 

 testing its merits by its practical employment in some 

 English collieries noted for fire-damp. 



After an intere'-ting paper by Mr. D. Rowan, of 

 Glasgow, " On the rise and progress of the iron ship- 

 building trade in .Scotland," which, however, w.js of a 

 purely historical and statistical nature ; the next com- 

 munication was made by Mr. Lauth, of Pittsburg, Unittd 

 States, " On Lauth's system of rolling iron by three high 

 rolls." The improvements proposed in this sys'em of 

 rolling, which is in itself very old, consi-^ted m makng the 

 central roll of less diameter than the two others, which 

 are of ordinary size, and in having it fixed, whilst the two 

 others are adjustable by screws. In the hard rolls the 

 bottom roll alone is diiven, both the middle and top roll 

 being carried round hy friction. All expansion or con- 

 traction is prevented by a stream of water cons'antly kept 

 running on to the roll ; and gieat rapidity in rolling, as 

 well as economy in labour, is claimed fir this s\stem. In 

 the discussion which followed, t^c general opinion ap- 

 peared to be that, although such rolls were well adapted 

 for plates, in this country they were less ad?p'ed for 

 rail rollinj, owing to the greater difficulty in adjusting 

 the grooves so as 10 turn out rails as cotrrct in section as 

 was insisted upon by cur and most of the Continental 

 engineers, but not in the United States ; also because 

 the necessity for three rails would s'ill further augment 

 the immense Jtock of lolls reouisite to suit the mu't'plicity 

 of sections required in the English trade, as well as in- 

 crease the labour and time rccpured in changing the rolls. 

 The next paper was by Mr. A. Spe-ncer, of West 

 Hartlepool, "On further improvemems in Spencer's 

 Rotary Puddling Furnnce" a model of the furnace in it"; 

 present foim bemg exhibiied, and its construction, mode of 

 fettling, and working, fully entered into hy the author ; 

 after which, owing to time not permitting, a h ngthv paper 

 by Mr. J. Guildford Smith, (f Philad'r Iphia, " On the 

 \Vestwsrd development of the Iron Manufaeture of the 

 United States," was taken as read ; and after passing votes 

 of thanks to the Loid 1 rovost and civic authorities of 

 Glasgow, the Council of the Philosophical .Society, the 

 Committee of tfie Royal Exchange, the local Commi'tee, 

 and the President of the Institute, the proceedings of the 

 meeting were brought to a close. 



In the afernoon an excursion was made by a spcci;il 

 train to the Coltness and Mossend Ironworks, the 

 members of the Institute being entertained on thcr re- 

 turn at a banquet given in the Corporation Galleries by 

 the local Committee of the Institute. 



An interesting feature in connection with the meetirg 

 was the arrangement of a temporary museutn in the Cor- 

 poration Galleries containing models, specimens, and 

 objects of all kinds bearing more or less dirccily on the 

 Iron and Steel manufacture, many of the articles exhibited 

 being of great interest. 



LETTERS TO THE EDITOR 



[ The Editor does vpt hold himself responsible for opinions express.'d 

 ky his cc?respo»dnds. No notiee is taken of anonvmous 

 communications, ] 



Solar Outbursts and Magnetic Storms 



Im ihe French dviiples f:,ird:is of Angus* 4, which has lately 

 reacheH this rountrv, is an acioiint by Father Secchi of a re- 

 markable ou'bur^t trnm the sun's l-ipti wimessed hy him on 

 liily 7, which Instfd frnm 3h 30"" to 6>i 50™ (Roman lime, I 

 presume), or nearly 2^ 40"^ to t^ o"' {Greenwich tinie). 



A majjnetic storm cummenced at Greenwich at 5'" c'" prtci-e'y 

 on the same day, I's indications b<'gan at that time " ith iinusiial 

 suddt-nness and strengih, on all the m ■gnetic indicators, narre'y 

 the declinatii n-nec'llr-, ihe hniizontal force matinftometer, the 

 vertical force magnetometer, the t-arth-nnrent wire, inan?pprnxi- 

 mate N.E. and .S.W. direction, ai'd on thee-ar h-curienl w ue in nn 

 approximate N. \V and S E. direction The disturbance bsted, 

 gradually dimiiii^^hing, to the evening of July 9. During a part 

 1 ui the time it was acce>mpanieel with aurora. 



I do not venlure upon the question wheiher there really was ] 



any connection between the solar ovithur^t ard the teires'rial \/ I 

 magnetic storm, bin I will remaik th.it, if there was such con- 1 



neclion, the transmission of the intlufucc fie/Ui the siiu to t| e 

 earth must have occupied 2^ 2c"^ ; or a longer time if Father 

 .Secchi did not .see the real beginning of the ou'bur>t. This, if 

 estatili^hed, would be an imjieirtant cosmical fact ; and, at any 

 rate, ihe notification of this apparent retarda'ion may diiej'- ihe 

 attenlion of observers of sinular phenomena in future ... .. new 

 element in tVieir interpretation. G. I!. At Y 



Koynl tJb'eivatoi y, (Greenwich, August 14 



Ocean Circulation 



AT.Tliot'Gir no mathematician, anel only an amateur in ijhysics, 

 it appears 10 me that the ehfliculties and objections of Mr. Croll 

 on ttds suli)ect may be obviated, and the whole questi* n e'uci- 

 elated by a ref* r<^nce to the admitted facts, and a c mmon sense 

 interprt-tation of them. And first, as to the fact that the surface 

 water of the Atlantic Ocean, m moving northwards from the 

 equator to 60" lat., has almost wholly lust the easterly mo'ion e.f 

 rotation it shmild have hroiight «iih it. This loss is inif uted hy 

 Mr. Croll to friction onlv, and he argues that the mucfi lower 

 velocity of ihe northward current must, iheref.Te, be wholly 

 neutralised by friction. 'I his is his main argumert, which he 

 has repeatedly a.iduced, and to which he has hitherto lec^iveel 

 no reply. But, although his reasoning might he admi'terl if the 

 conditions affecting the two motions were the same, it seems to 

 me to be quite inappbcahje to the present case. If, in the tem- 

 perate ziiiie. the ocean t-xtended iininrerruptedly in an east and 

 we-t direction louiid the gl 'he, it would no doubt retain a con- 

 sideraVtle portion or the equat 'rial ea..tem motion, and whatever 

 dehciency existed might fairly he impute cl to friction. Hiit the 

 Atlantic is actually like a huge lake, with continuf'us eastern 

 anel western shorrs, anel the water which flows northwards 

 along the eastern shore is ]n"evenifd from moving ea^twa ds, 

 not by friction against waer or even against the shore, but by 

 having to perform uoik in liftingor heapng up tre water .aga-rsi; 

 t'.e sh.ire, Hist ijs the water of a pona or lake :s heaped up on 

 the leev.ard side ly a s'roui.' wIu^h. As ihe <'irecli"n of the 

 motion eif the water will, however, by the hypothesis, be obhque 

 or sompwha' north ol east, some i f the nioiion will be riiverieel 

 northwards along the ea-t<-rn shore, anel thus tend to incre'ase Ihe 

 nnr hTly flo^'. The 9,925 pounds of em rgy (according ui Mr. 

 Croll) are not therefore consumed in overcoming the Iricliemal 

 resistance to eastwarel motion, but for tiie mo^t part in cUtV g the 

 acti;al work of overcomii g graviiaticm and holding up ihe waters 

 at a higher level, and the theoretical nnioun* of tfiis rise can, no 

 doubt, be easily calculated for us by Mr. Croll. 



The case of the water moving northward is very different. 



