-i^ 



May 2G, 1882.] 



KNGVVL.EDGE 



629 



WEATHER CHARTS FOR WEEK ENDING MONDAY, MAY 15. 





'^1 X :i: i / cX 



Explanation of Charts. — The two charts for each day show the general condition of tho weather over Western Europe at 8 a.m. 

 In the upper chart the height of the harometer is expressed by "isobars," tlie value of each line being ^'iven in figures. The 



prevalent winds aro shown by arrows, which are drawn flying \cii\ the wi7id, the force being indicated thus : ^? ^- = a heavy 



gale; ^ ;*■ = a g;ile ; >- ■• a fresh to strong brcc/.o ; ^" = a light to moderate breeze; and O == a calm. In the 



lower chart tho weather is indicated as follows: — b = blue sky ; c = detached clouds ; o = overcast; m = misty (haz}-) ; f = foggy; 

 (J = Fqualiy; r = rain; h = hail; s = snow; I = lightning; and t = thunder. The general distribution of temperature is shown by 

 '* isotherms, " and the rcadir.gs at certain places are given in figures. Diagonal lines = rough sea, the shading being proportional to the 

 disturbance. 



The above arrangement has been devised in response to a great number of suggestions. It will, probably, be that which we 

 shall eventually adopt for good ; but we may be able, perhaps, hereafter to carry the charts to a later date each week. If so, this 

 will be done without break of continuity. 



^otfS on Slit anil ^ricncf. 



Fire Risks and Electric LiGnxixo. — The Society of Telegraph 

 Engineers and of Electricians have appointed a very influential 

 committee to consider and report upon the rules which they would 

 recommend for adoption for the prevention of lire risks arising from 

 the use of the electric light. 



Crvstat, I'ai.ace Exhibition. — As at present arranged, the 

 Electrical Exhibition at tho Crystal Palace will close on Juno 3. 

 Already scvoril exhibitors have begun the work of removing their 

 goods. The Right Hon. tho Speaker and a number of Members of 

 both Houses of Parliament, including the Electric Light Committee, 

 will visit the Exhibition on tho 27th inst. 



Encinkebing. — At an extraordinary meeting of tho Society of 

 Telegraph Engineers yesterday week (18th inst.), Mr. Stroh re- 

 peated his admirable lecture on " Attraction and repulsion duo to 

 sonorous vibrations, and comparison of the phenomena with those 

 of magnetism." On the occasion of the first delivery, the iiife of 

 the worlil of physical scientists attended, and it is universally ad- 

 mitted that Mr. Stroh, by his marvellously-executed experiments 

 and lucid ixplanations and deductions, has gone a long way towards 

 demonstrating tho nature of magnetism. 



Electro- JLagnetic Repulsion. — At the Physical Society on 

 Saturday, 13th inst.. Professor Guthrie exhibited his modification 

 of At^go's experiment, in which a rotating disc of copper repels a 

 horse.ihce maj;net suspended vertically above it from the end of a 

 chemical balance beam ; a plate of glass being interposed between 

 the disc and m:ignet to prevent the air from disturbing tho results. 

 Professor Guthrie gnve a table of observations made on the re- 

 pn'sive force for different speeds of rotation of the disc, and these 

 showed th^t the repulsive force varies in proportion to tho square 

 of the speed of rotation. 



Electric Fire- Alarms. — In the annual report of Captain Shaw, 

 chief of the Metropolitan Fire Brigade, it ia pointed out that by 



reason of the system of electric fire-alarms and the excellent tele- 

 graphic intercommunication between stations, &c., the various fire- 

 engines and men of the brigade can bo concentrated on any given 

 spot in a very much shorter time than was formt^rly tho case. 

 Captain Shaw reports that the electric fire-alarm system has been 

 fcftind to work well, and it is to be greatly extended. 



TnE Recent Magnetic Storm. — Tho curves given by the Kew 

 magnetograph during the week ending April 22, when auroral dis- 

 plays were so common in America, and earth currents so prevalent 

 iu the inland telegraph lines and Indian and Atlantic submarine 

 cables, clearly indicate a severe " magnetic storm " or disturbance 

 of the terrestrial magnetic field. According to Mr. Whipple, tho 

 indicating magnets at Kew were somewhat disturbed on Ajiril 14, 

 but remained quiescent until the night of the 16th, when they 

 became strongly affected at about 11. ta p.m., and from that time 

 the storm raged until 8 P.M. of the i7th. The maximum reduction 

 in the earth's magnetic force took place at 6 a.m. of the 17th, and a 

 little after noon on the same day both forces became so increased 

 that tho registering speck left the field of tho receiving instru- 

 ment for nearly two hours. A second period of disturbance 

 began about 3.40 A.M. of tho 20th, which was violent up till 

 about 2 p.m., and gradually diminished in intensity until 

 7'4.5 a.m. of tho 21st. During this period the magnetic force 

 fluctuated largely, but not to the extent occurring on tho 17th. 

 Tho fact that there were at the time two unusually large spots 

 cro.xsing the snn's disc is certainly in support of the theo that 

 these magnetic storms are associated with sun spots. Mr. Whipple 

 acccunts for the abrupt commencement of magnetic storms by 

 the sujiposition that possibly a sun spot only produces such an 

 effect when cutting certain lines of force, which he imagined might 

 extend for a limited angular distance around the earth's radius 

 sector. It is to bo hoped that magnetic observatories will bo multi- 

 plied, especially in the southern hemisphere, as Professor W. G. 

 Adams has pointed out, and it is satisfactory to learn that the 

 French (iovernment have decided to equip such an observatory at 

 Cape Horn. 



