Ch. II] LIGHTING WITH DAYLIGHT AND A MIRROR 53 



M. Luckiesh. Artificial Daylight. Science, N. S., vol. 42, November, 1915, 

 pp. 764-765- 



Henry Phelps Gage. " Daylite Glass," a color screen for producing day- 

 light artificially. The Sibley Journal of Engineering, Ithaca, \. Y., Vol. XXX, 

 No. 8, May, 1916. 4 quarto pages, 6 figures. 



Simon H. Gage and Benjamin F. Kingsbury. Some apparatus for the 

 microscopical laboratory. Anatomical Record, Vol. X, No. 8, June, 1916, 

 pp. 527-536. 7 figures showing the use of the daylight glass for microscopic 

 work. 



Anthony J. Brown. Some uses of artificial daylight in the psychological 

 laboratory. American Journal of Psychology. July, 1916, Vol. XXVII, 

 pp. 427-429- 



Lighting Experiments with the Simple Microscope 



§ 93. Opaque objects. — For these the light strikes the surface and 

 is reflected, mostly in an irregular manner so that the object can be 

 seen almost equally well illuminated from any angle. Ordinarily 

 the daylight falling upon the object will sufficiently illuminate it, also 

 the light of a lamp. 



Place a printed page in bright daylight or near a lamp where the 

 light can shine upon it and then look at it with the simple microscope 

 held in the hand, on the legs of the tripod (fig. 4, 17-19) or held by a 

 special stand. By varying the distance between the microscope and 

 the object one can soon find the best focus, and by changing the 

 position of the object, the best position for the light available. 



Of course if one wishes to discriminate colors precisely, daylight, 

 natural or artificial, must be available. 



Take some object in the hand and hold it in a good light and then 

 look at it through a simple microscope held in the other hand. 



Remember in using the simple microscope that the eye should be 

 near the microscope to see the largest field (§ 15, 47, 57), and, as will 

 be more fully shown when dealing with magnification, the nearer the 

 object is to the principal focus the greater will be the apparent increase 

 in size (fig. 13-16). 



Lighting Experiments with the Compound Microscope 



§ 94. Daylight with a mirror. — As the following experiments are 



for mirror lighting only, remove the substage condenser if one is present 



(see § 100, for condenser). Place a mounted fly's wing under the 



microscope, put the 16 mm. or other low objective in position, also 



