72 THE POPULAR SCIENCE MONTHLY. 



the acquired color of the glass. Among the gathered specimens was 

 one of crown-glass, set in a church in Lexington, Mass., in 1794, from 

 which the windows were removed in 1846, and afterward used as 

 covers for hot-beds. The original color, ascertained by removing the 

 putty from the edges, was a light green, and that produced by seventy- 

 three years' exposure, a purple. Mr. Gaffield's efforts have also been 

 directed toward examining the old cathedral-glass of Europe, Avhere 

 such observation is practicable. He still continues with great enthu- 

 siasm the experiments begun eleven years ago, and carefully records 

 the results of his observations on a well-known phenomenon, " in the 

 hopes that they may add some mite to the sum of human knowledge, 

 and may stimulate and aid those who are better versed in scientific 

 studies, to ascertain the causes and exact operations of this interesting 

 power of the sun's rays to paint the products of art, as they do so 

 beautifully and wonderfully the works of Nature on the mountain, in 

 the forest and field." 



MEASUEES OF MEIS^TAL CAPACITY. 



By J. W. EEDFIELD, M. D. 



SCIENCE cannot look otherwise than favorably upon every attempt 

 to determine the quantitative relations of mind and body ; and much 

 ingenuity has been expended in the effort to arrive at a geometrical ex- 

 pression of it. Aristotle, "the father of Natural History," as Prof. 

 Agassiz calls him, speaks of an angle of the forehead to an horizontal line 

 of the face as an indication of intelligence, and it is evident that the 

 Greek sculptors designedly represented the superhuman attributes of 

 the gods by an angle exceeding that of the highest human. It is not 

 strange, therefore, that, when Camper restored the lost science and art 

 of the measurement of psychological development, under the name of 

 the Facial Angle, in 1784, the scientific world gave it a cordial wel- 

 come. But of course it could not be accepted as veritable scientific truth 

 without running the gantlet of the severest criticism. Its most vul- 

 nerable point was a claim to be something more than ^ mere general 

 rule, applicable to the designation of the rank of a species or of a race 

 in the scale of intellectual and moral elevation. It claimed to be ap- 

 plicable to the distinction between nationalities, and even between 

 individuals of the same class of society, both as to facial and as to 

 mental characteristics. This was too much, and on this ground Blu- 

 inenbach and others attempted to demolish it as a rule altogether, and 

 by very many were supposed to have succeeded. Like other favor- 

 ites, it had the misfortune to be made too much of, the consequence 

 being that it came to be treated as of little worth. And yet nearly 

 all comparative anatomists and physiologists make use of it as a 



