NATURAL HISTORY NOTES. 
141 
“ A Warning from the British Coal-Fields” is the title of a pam¬ 
phlet published in Liverpool, which advocates the formation of a 
national association, the purpose of which should be to inquire into 
the exhaustion of our coal. At the present rate the author thinks 
British coal will come to an end in 110 years. It is to he regretted 
that such an alarming statement should he made except on the most 
trustworthy authority. We call attention to this pamphlet mainly to 
remind our readers that the Royal Coal Commission, whose report was 
published in 1871, gave nearly 450 years for the duration of the coal to 
the depth of 4,000 feet. In the zone exceeding that limit a quantity 
of coal which amounts to 48,465,000,000 tons is believed to exist. 
Eyes on Shells. —Professor Moseley has lately discovered 
the presence of eyes on the shells of certain Chiton id®. They are 
restricted to the exposed areas of the outer surfaces of the shells—that 
is, to the tegmenta of Carpenter. Each eye lies in a pear-shaped pit, 
which is covered externally by a calcareous cornea. The cavity of the 
pit is lined by a dark brown pigmented substance, which curves 
inwards beneath the cornea, forming a sort of iris. The lens, which is 
perfectly transparent, hyaline, and strongly bi-convex, lies behind the 
iris aperture. The fibres of the optic nerve, within the pigmented 
cavity, become separated from one another and loose, and pass directly 
to a retina composed of a single layer of short well-defined rods. The 
absence of eyes has hitherto been regarded as a characteristic of the 
Chiton id®, and the ignorance of their existence is, perhaps, due to the 
fact that they do not occur in any common European representative ; 
they are not easily seen in dried specimens of shells, which require to 
be moistened with spirit before the eyes become visible ; and Schizo- 
chiton, in which they are largest and most evident, is a rarity in 
museums. 
Coloured Sounds. —It is said that the blast of a trumpet has been 
compared to scarlet, and a serious dissertation has been written on 
the problem “ Of what colour is A flat.” But, joking apart, the 
phenomenon of coloured hearing has now a recognised scientific place. 
In “ La Nature,” April 18tli, 1885, M. de Boclias gives an account of 
several observations which have been made on the subjective colours 
associated with sounds in certain persons. A man examined by Dr. 
Pedrono, of Nantes, perceived a different colour for each musical 
note; neighbouring notes produced similar colours: the high notes 
were accompanied by brilliant colours and the low by sombre ones. 
A musical chord produced a single colour, the resultant of those due 
to the separate notes; if the chord contained a dissonance, the colour 
proper to that appeared as a detached patch near to the other. 
Human voices appeared coloured according to their timbre; yellow, 
red, green, and blue voices could be distinguished, the blue voices 
being the commonest; green voices were very rare. An Italian, 
Doctor Z., examined by M. Ughetti, attached different colours to 
different vowels ; thus a was black, e yellow, i red, o white, and ou 
coffee-coloured (the vowels of course bearing their continental pro¬ 
nunciation.) In conversation the rapid succession of vowels generally 
prevented the Doctor from perceiving the colour due to each; but if a 
word contained the same vowel several times repeated then the colour 
became distinct; thus ballata was black, neve yellow. Other similar 
cases, differing, however, in their details, are known, and M. de Rochas 
promises to describe one which he has himself met with, still more 
interesting than those now given. 
