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Proceedings of the Royal Society 
On the 20th of January 1834, he was elected a Fellow of the 
Royal Society of Edinburgh, and in December preceding he contri- 
buted a paper to our Proceedings (vol. i. p. 31), “ On a New Species 
of Coloured Fringes developed between certain pieces of Plate-Glass, 
exhibiting a new Variety of Polarisation, and a peculiar Property 
which renders them available for the purposes of Micrometry.” 
The author found that the fringes presented the appearance of three 
rectilinear bands, each consisting of black, white, and coloured 
stripes, but the central band was afterwards found to be composed 
of two united into one. There is thus a band for each of the four 
surfaces of the plates, and these bands possess a property which he 
thought might be available for micrometry. When the surfaces of 
the plates are parallel, two of the bands are united into one at the 
centre; but if a film be introduced between the plates, so as to 
cause them slightly to diverge, the two bands in the centre will be 
separated, and move laterally from each other, still preserving 
parallelism. A film, of an inch in thickness, causes the central 
bands to separate to the distance of an inch, so that every of an 
inch of separation is equivalent to L__ an thickness. 
On the 16th of January 1837, he read a paper to our Society on 
the condition of the earth, as it is first described in the Mosaic 
account of the creation. In this paper, he held that in a philo- 
logical point of view, the most correct translation of the words 
rendered “ without form and void,” is immeasurable and imponder- 
able. He seemed to lean to the opinion that the strata of the 
earth containing organic remains were formed during the very epoch 
embraced in the Mosaic narrative, and that the primitive condition 
of the earth was properly gaseous. In this connection, it may be 
mentioned, that his theoretical knowledge of music was uncommon, 
and that he arranged to music a metrical translation of the Psalms 
from the original Hebrew. 
Having proposed the micrometer above described, Mr Ponton 
subsequently devised a photometer, which he described in a paper 
read to this Society on the 14th of March 1856, and published in 
our Transactions (vol. xxi. p. 363). The principle of this instru- 
ment consisted in comparing lights of different intensities by 
judging of the relative brilliancies of two definite surfaces when 
illuminated from two sources of light to be compared, care being 
