FOR MICROSCOPICAL ILLUMINATION. 6 



To obtain the best possible result it is necessary that the roll 

 be very carefully placed with regard to the flame, and for this 

 purpose the burner must be raised or lowered or otherwise 

 adjusted until the best effect is obtained, which, if properly done, 

 should result in the production of a beautifully clear white light. 

 It will be understood that coal gas alone is generally used for 

 this light and that the higher the pressure the whiter the colour ; 



anything under 4 inches is unsatisfactory. Of course it may 

 be used in conjunction with oxygen, when its brilliancy is re- 

 remarkable bearing in mind the small quantity of gas used. 



This method of illumination I have used with great success 

 and satisfaction for more than fifteen years both for photo- 

 graphic and visual work, and only find it necessary to revert to 

 limelight or oil when special circumstances demand them. 



I wish by no means to make exaggerated claims on behalf 

 of this light, but am sure that any who try it will find it a most 

 cleanly, useful and economical source of light. Though by no 



