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XXI. Account of an experiment on the elasticity of ice. By 
Benjamin Bevan, Esq. In a Letter to Dr. Thomas Young, 
For. Sec. R. S. 
Read April 27, 182 6 . 
DEAR Sir, Norwich, January 18, 1826. 
X have been long desirous of repeating my experiment on 
the elasticity of ice, but until the present frost have not had 
an opportunity for two years, when I had but a single speci- 
men, and rather too small, and which broke soon after the 
commencement of the experiment. From that experiment I 
had calculated a modulus of 6.000,000 feet ; but finding the 
result of my experiments in the present season much less, 
and pretty uniform amongst themselves, I re-examined the 
calculations made in 1824, and have discovered an error, 
which had before escaped me, in the reduction, and which 
brings the result of that experiment to agree with those made 
in the present season, or about 2.100,000 feet. I will not 
answer for the absolute correctness of the second figure, be- 
cause a variation of the of an inch in the thickness of the 
specimen will change this figure. 
The present severe frost has enabled me to try experi- 
ments on a much larger scale, and upon ice from 1^ to 
4 inches in thickness : to explain the mode I adopted with ice 
of near 4 inches in thickness may be necessary, and was as 
follows : 
Upon a large pond within less than a mile of my residence 
at Leighton Bussard, the depth of which I found to be about 
