480 Mr. Vonlton'ti f 11 rtJter experiments upon 



testing the effect of gold surroundings in darkness. It was then 

 covered witli rugs, inats, &c. 



At other times it was placed on its side, with the open end 

 closed by a sheet of clear glass dkected towards a strong light. 



XVII. A very similar cylinder, 2'42 decimetres diameter, 

 1*16 high. Half the internal surface was lined with polished Dutch 

 metal, and one open end closed by the same. When placed on its 

 side the gilded surface was uppermost and formed a roof, while 

 the covered end formed a background. When placed on its open 

 end the latter formed the roof. 



This and the succeeding gold receptacles were always used in a 

 strong light, unless otherwise stated. 



XVIII., XIX., XX., XXI., and XXII. Five small cylinders, all 

 about G'2 centimetres diameter, 8*4 high. They were always 

 placed on the open end on a floor of white paper or poUshed 

 Dutch metal. A polished Dutch metal roof sloped from the 

 front part of the upper end to the back part of the lower end (m 

 the position placed during use), so that little more than half the 

 capacity of the cylinder was available for larvte. The clear fiMUt of 

 the cylinder was placed so as to face a strong light. 



XXIII. A similar cylinder, lined in the same manner with 

 Dutch leaf. 



XXIV. and XXV. Two similar cylinders, also lined with Dutch 

 leaf, but the roof sloped much less steeply from the front to a poiut 

 about I down the back of the cylinder in the case of XXIV., about 

 1 in XXV., so that nearly the whole of the capacity was available 

 (about I in XXIV., and much more in XXV.). Below the level at 

 which the roof joined the back, the latter was lined with the 

 same gilt paper, extending round half the circumference of the 

 cylinder. 



XXVI. A rather taller cylinder (I'Ol decimetres), of the same 

 diameter. The sides were gilt two-thirds roiuid, and tbe gilt paper 

 brought together to form a ridged roof with very sloping sides, the 

 ridge running from back to front. There were deep shadows in the 

 higher part of the roof within the ridge, which was nearly 2 centi- 

 metres higher than the cylinder. About two-thirds ot the capacity 

 was available. Owing to the gilt lining extending so far round the 

 cylinder, the clear fi'ont was reduced, and the gold surface much 

 less illuminated than in the other small cylinders, XVIII. to XXV. 

 The gilding was polished Diitch metal. 



XXVII. A tall cylinder, the same dimensions as IV. ; lined in 

 the same manner as XXV., with embossed Dutch metal, so that 

 nearly the whole capacity was available. 



XXVIII. A similar cylinder, treated exactly like V., except 

 that the black paper outside the glass was replaced by polished 

 Dutch metal. 



XXIX. A tin box, 2'35 decimetres long, 1*07 wide and deep; 

 placed on end with glass sheet in front. There was a sloping roof, 

 as in XVIII., so that about half capacitj' was available. On the 

 floor and a small area of bottom of sides the bright tin surface was 

 exposed, but the rest was gilt. The gilt paper was crumpled to 

 make cavities and reflections in all directions. The gilding was 

 embossed Dutch metal. 



