46 



PRACTICAL PHOTO-MICROGRAPHY. 



The lamp should be on a heavy stand, and for convenience 

 should slide up and down a stem as shown in our cuts. About 

 an ounce of camphor may be added to each pint of the oil used, 

 which should be paraffin of the very finest quality that can be 

 obtained. Bad oil causes no end of trouble. The wick must 



FIG. 13. BAKER'S "NELSON" LAMP. 



be kept well trimmed, and all parts of the lamp scrupulously 

 clean. The slips of glass used in front of the flame in the 

 metal chimney are very apt to break when the flame is turned 

 edge toward the microscope ; to prevent this the slips should 

 be rolled in a piece of cloth and boiled for two hours in water, 

 or, still better, in sweet oil. 



