Aug. 21, 1S85.] 



♦ KNO\VLEDGE 



<Bm Inbfntoi<5* Column. 



SHIPS' SIGXAL LAMPS. 



[Patent No. 15,l-i7. 188i.j— This invention, by Mr. Edwin 

 Martin, of C8, West India Dock-road, Lojidon, E., is intended as a 

 means of ensuring better light and absolute freedom from being 

 extinguished by the violence of the weather, irrespective of its 

 severity. It is, therefore, entitled to greater consideration for the 

 prevention of collisions at sea, which are too frequently caused 

 through the Lights becoming extinguished. 



It has two lenses, an outer and an inner, either of which may be 

 coloured; between the two lenses there is a space, about li in. 

 wide, for the purpose of admitting a ciu-reut of air between them, 

 the object being to keep them cool. 



The inner lens is fitted inside the body of the lamp, and a shield- 

 plate is so fixed to the lens and sides of the lamp as to prevent 

 any up or down draught coming into contact with the light. 



The shield-plate, which is the chief novelty, is fixed to back and 

 sides of the lamp. It is bent conical, and is left open at the top end 

 under the raised top of the lamp. 



The outer lens is fitted to a hinged frame, for the more ready 

 convenience of keeping it clean and preventing an accumulation of 

 dirt whereby the full advantage of the light may become un- 

 obtainable. 



At the bottom of the lamp is a row of air-holes, so constructed 

 as to maintain a clear current of air, and allow it to pass away 

 either top or bottom. 



The lamp is proof against being extinguished either by wind or 

 water, without regard to its application. 



Colza or petroleum oil may be used for burning, and the method 

 for trimming is similar to that adopted in the ordinary signal 

 lamps now in use. 



The body or frame of lamp may be made any size or 

 material. 



Trials of Mr. Martin's Lamp have been made with the top open. 



1st. — A blast generated by a fan driven by steam power was 

 played on it from every direction; this trial lasted about ten 



2nd.— The lamp ■ 

 held under w 



bein 



n through a trough of w 



n feet long, 



—Water from a fire-hose was played on the lamp from all 

 directions for about ten minutes, the top being left open. None of 

 these trials produced any effect. 



The lamp had been lit about half-an-hour before the trial took 

 place, so that the metal and glass had plenty of time to heat. 

 It must be admitted that by a very simple and inexpensive 

 contrivance, the patentee has accomplished what he claims for it — 



It cannot be blown out by the wind or put out by water, and is 

 so constructed that the lenses will always keep cool. 



These lamps appear to be exceptionally well suited for large or 

 small craft, such as coasters and fishing-vessels that usually carry 

 their lights near the water, as they are not liable to be blown 

 or jerked out by the quick motion of such craft ; neither would 

 " ' ' e damaged or the light affected by sprays or seas going 



ir them. 



' rncuRsixG Mirr.oscnrr adjustment. 



an inch, thus 



c for all kinds of high- 



Only a small j^roportion oj Letters received can possilly he inserted. 

 Correspondents vtust not be offended, therefore, should their letters 

 not appear. 



All Editorial communicaiions should he addressed to the Editor of 

 Knowledge; all Business communications to the Publishers, at the 

 Office, 74, Great Queen-street, W.C. 



DELAYS ARISE FOE WHICH THE EDITOR IS 



The Editor is 



All Remittal!, 



payable to Mes: 



tsihlefor the opinions of correspondents, 

 es, and Post-Office Orders should he made 



METEORIC DISPLAY. 



[187-1] — I should be very glad to hear through Knowledge that 

 other readers noticed the meteoric shower that occurred on Monday 

 evening between 9.15 and 10.40. At the same time a brilliant 

 display of lightning illuminated the sky on the eastern horizon. 



AH the meteors appeared to diverge from a point just below 

 Cassiopeia in the Milky Wav. The brightest fell from the zenith 

 in a S.E. direction, about 9.26. When near the horizon it burst, 

 the particles being of a very intense blue colour and formed a tail 

 like a comet's, which was visible for fifteen seconds. 



Several others were seen, but none so bright as the one 

 described. 



At 10.40 the sky became overcast with clouds. 



Bracebridge, Aug. 10, 1885. Jas. Grant. 



[The display belonged to the well-known August shower— the 

 Perseids.— E.P.] 



METEOR SHOWERS. 



[1875] — I should feel much obliged if you would clear up some 

 difficulties in my mind on the subject of meteor showers. 



Some years ago I read with the greatest interest a lecture 

 delivered at the Royal Institution, on Feb. 14, 1879, by Mr. G. J. 

 Stoney, F.R.S., on the " Story of the November Meteors." Your 

 articles on meteors in this year's Knowledge considerably discount 

 the value of this otherwise most interesting lecture. To account 

 for these meteors which once travelled together, afterwards 

 lengthening into a procession, he conjectures that the November 

 shower was once (in a.d. 120 probably) a cluster close to Tranns, 

 when the individual meteors, being perturbed in gi-eater or less 

 degree, tended to separate, those most attracted lagging behind. 

 Furthermore, he says atp. 9— "As the comet (with "a cluster of 

 meteors within it) swept past the planet, its outly 





o have 



swhat r 



azod h 



urfac 



lan the 



n the 



ahead of the come 

 the point of ovrr 

 brought together :' 



allolllin- i;,,.. :: 



to the said li. 

 tube, this is I-l I 



lensof the obi. (live 'i 

 use of higher powers tl 

 the microscope tube, 

 adjustment over the m 

 eyepiece and objectiv( 

 action. Although i' " 



y meteors of this shower be se 



, 1 take it, 

 ^ lying in 



., ,.,.,. ii long way 



Sov. 11. 



n next November ? 



