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TRANSACTIONS OF THE SECTIONS. 53 
reflections of the human voice, by this means, be prolonged, the re- 
flection of one letter falls upon the original sound of another letter, 
and occasions as much derangement as if one syllable or word were 
intermixed with another syllable or word ; as one letter differs in sound 
from another letter as much as do syllables or words. This is one 
great and leading error in the construction of places for public speak- 
ing; and it is alone sufficient to show how fallacious the idea is of 
relying on the mere form of an apartment, without attending to and 
regulating this action, in not only the walls and ceiling, but in every 
reflecting body in an apartment, especially in glass, which is the most 
sonorous material. 3rd. The same rules of action are exhibited in 
water. In the ocean, the reach of sound is regulated according to the 
expanse of water: where there is an indent in the land, the wave is 
extended, and the sound it produces is prolonged. Were this action 
regulated by the current of air only, the waves would pass in one uni- 
form direction; but this is not the case. 4th. These principles of 
action are, however, more perfectly defined in the atmosphere, through 
which sounds are transmitted with least change, and are preserved 
separate and apart from each other. 
Having in view mainly the economy of speech in apartments, Mr. Shand 
stated the following facts and reasoning: An individual who is so deaf 
that he is insensible to upwards of a thousand people singing in a church, 
on applying one end of a forked piece of wood to his teeth, and the 
other end to the ledge of the division of the seat before him, is enabled by 
this to hear and join in the tune. Now it is not merely the partial agency 
of this wood that is to be considered, as, by the spread of the atmosphe- 
ric vibrations, the voice sets in motion every atom of every solid in the 
church, and it is distributed throughout these with more rapidity and 
intensity than by the air, which is incapable of communicating the 
same measure of vibratory influence at any one given point; and it 
evinces that, being the more rapid and profuse conductor, it is the 
wood that is most rapidly set in motion, and communicates action and 
sound to the air ina room. If these observations be correct, nothing 
can be more erroneous than to suppose that speech can be regulated 
within the walls of an apartment without regulating the action of the 
solids, which predominantly govern it in this case. If sound predomi- 
nates more in the fibre of the wood of the stethoscope than in the 
a€rial passage in it, must not the same rule apply in a church, where 
the seats and lathing are almost invariably of pine ? 
Mr. Shand proceeded to remark on the peculiarities with regard to 
sound which he had observed in certain buildings. In the Albion Church, 
in Glasgow, he heard the speaker with perfect distinctness when he spoke 
in his natural tone, as his voice was mostly reflected by the walls, which 
are of solid masonry ; but when his voice was raised so as to act with 
more force on the ceiling, the longer excursions and undulations of 
the then hollow ceiling produced prolonged reflections, which drowned 
speech. In St. Andrew’s Church very different effects are produced 
in the galleries and lower part of it. In the galleries the ceilings are 
