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to PUcroSfoptetS. No. IV. 



XV. PRACTICAL POINTS CONNECTED WITH ILLUMINATION, ETC. 



By Daniel Cooper, Surgeon, SfC. 



Lamps for Microscopic Purposes. There is perhaps no greater diffi- 

 culty the Microscopist has to contend with in his evening examinations 

 than the obtaining a certain and sure light. It is a general opinion 

 that there is none so certain, and can be equally relied upon, as the ordi- 

 nary Argand lamp, well trimmed, and burning the very best sperm oil. 

 But as the price of sperm oil is high, expedients have been resorted to 

 out of number to burn vegetable oils of a much lower price, with the 

 same advantage. Lamps trimmed with these oils, require either con- 

 stant use, or being constantly and regularly cleaned ; otherwise the oil 

 becomes thick, clogs up the tube which conveys it from the reservoir, 

 and the cotton becomes in like manner clogged, so that all capillary 

 action becomes arrested, and it requires changing nearly every time that 

 it is used, provided it is not constantly burned, and even then it becomes 

 necessary to clear the tube occasionally. For the purpose of ensuring 

 as complete combustion of these cheap oils as it is possible to obtain, 

 many plans have been devised. Those most deserving of attention are, 

 the Patent Oxydator, invented by Mr. Young, and the means devised by 

 our correspondent Mr. George Gwilt, at page 56 of the first volume. 

 Of these two contrivances that of Mr. Gwilt is considered preferable to 

 the Patent Oxydator, as in case of the glass being broken it is the more 

 readily obtained and renewed. The expense is much about the same. 



Asa portable means of illumination for microscopic purposes, and 

 which may be readily carried in the pocket without the slightest incon- 

 venience, is the Portable Candle Lamp, first made by Mr. George Jack- 

 son; it burns the candles manufactured by Molyneux and Co., which 

 require no snuffing; these lamps may be obtained of Mr. Ross, Optician, 

 Regent Circus, for six or seven shillings. 



The light of coal gas answers admirably where it can be conveniently 

 made use of. In those houses where gas is laid on to the sitting-rooms, 

 as to chandeliers, a flexible tube may be readily adjusted to one of the 

 pipes, which will convey the gas to a moveable gas lamp on the table 

 beneath, as first done by Mr. George Lowe. 



In cases where neither oil or gas illumination can be obtained, a por- 

 tion of a wax candle in a low candlestick is to be preferred to a number 



