290 On the Magnetism i/npiessed on Metals. 



sparks, drawn from a common electrical machine. Small steel 

 needles, placed in the interior of these spirals, were thus mag- 

 netized in a few instants, and the direction of their magnetic 

 polarity was found to be determined in reference to the surfaces 

 charged with the resinous or vitreous electricity, precisely as 

 happens with the copper and zinc poles of the voltaic ap- 

 paratus. Sir H. Davy has also obtained similar results, by 

 passing common electricity along a simple metallic wire, in 

 the vicinity of which, small steel needles were placed at right 

 angles to its length. 



Art. VIII. Description of a new Sinumbral Lamp: in 

 a Letter to the Editor of the Quarterly Journal of 

 Science and the Arts. 



Sir, , 



May I beg the favour of you to insert in the next Number 

 of your Journal, the following brief notice and sketch of a 

 new Shadowless Lamp, invented and manufactured by Mr. 

 Thomas Quarrill, of Bell-court, Doctors' Commons. 



I am, Sir, your constant reader, 



and occasional contributor, 



L. 



A section of Mr. Quarrill's lamp is represented in Plate V, 

 Fig. 2, from which it will be apparent that the oil reservoir is 

 so shaped as to conform with the direction of right lines issuing 

 from the brightest part of the flame, a portion of the light of 

 which is thrown down by a small reflector upon the circular 

 plate of ground glass, which fills the lower part of the lamp, 

 and which is surrounded by the oil vessel. Tlie chimney of 

 the lamp is constructed as usual, and the whole is surmounted 

 by a ground-glass light-distributor, so formed as to do away 

 all shadow from any portion of the lamp, and at the same time 

 not to offend the eye by any want of elegance in shape or 

 dimension. 



