xii Tranaactioihs of the Boyal Society of South Africa. 
Oedinaky Monthly Meeting. 
Amjust 17, 1910. 
The President, S. S. Hough, Esq., F.E.S., in the Chair. 
Dr. E. J. GoDDARD, Dr. M. Park, and M. M. Wessels were nominated 
for ordinary membership. 
P. J. Du ToiT, Dr. F. Engelenburg, and Miss D. Bleek were elected 
ordinary members. 
The Secretary, Dr. Peringuey, exhibited some flat slabs, artificially 
polished, and discovered in Strand-Looper-Hottentot sepultures. It was 
thought at first that these flat lamellae were braying implements, and, of 
course, they might, for that matter, have also been used efiectively as 
such. But another example was brought to his notice which shows con- 
clusively that their purpose was of a different nature. It was found in a 
rock-shelter and is covered on one side with a red pigment (oxide of iron) 
mixed with a fatty substance. It is not, however, a palette " in its true 
sense, but an implement used to besmear the body. The interest attach- 
ing to these palettes is that in shape, thickness, &c., they resemble similar 
utensils found in the Dolmens of Southern France (Aveyron) as well as in 
Egyptian tombs. 
" The Influence of Uniformity and Contrast on the Amount of Light 
Eequired," by H. Bohle. The author dealt first with the adaptability of 
the human eye to various daylight illuminations, and gave a new definition 
of glare : When the eye looks at an illuminant of great intrinsic brilliancy 
in front of a dark background it tries to do two things at once : To open 
wide for the dark background and to close up for the intrinsic brilliancy. 
The author then considered the physiological effects of radiation, explained 
overheating of the eyes due to excess of light absorption and considered the 
efi'ects of the ultra-violet rays of modern illuminants and of solar radiation. 
In addition he treated the effects of light radiation on germs of disease, 
the destructive action of rays when applied excessively, and finally dealt 
with the effect which uniformity and the avoidance of contrast in artificial 
lighting have on the amount of light required. He came to the conclusion 
that in a room with black walls an illumination of 35 to 40 candle-metres 
were required, whereas in a place with white ceilings and light walls the 
amount of light could be reduced to 30 candle-metres. For perfect uni- 
formity in such places, as obtained with inverted lamps, 20 candle-metres 
give, in the opinion of the author, complete satisfaction. The effects of 
various lamp shades on the uniformity of illumination were also shown. 
