The numbers marked thus are calculated from the experiments of Messrs. Hodgkinson & Fairbairn

Note-The experiments of Mr. Hodgkinson, from which the moduli of rupture of stones contained
in the last column of the above table have been calculated, together with those detailed in Art. 410.
form part of a more extended inquiry, which, when completed, will be laid before the Royal Society.
The crushing forces given in the above tables are in every case determined by the compression of
prisms of such a height as to allow the rupture to take place by the sliding of the upper portion freely
off, along its plane of separation from the lower (see Art. 406). The experiments of Mr. Hodgkinson
have shown that all results obtained without reference to this circumstance are erroneous. (See
Illustrations of Mechanics, p. 402.)

Imperial gallons in a litre

--1.5077222

=39-37079

=1.5951741

=3.2808992

=0.5159929

=10-764297

=0.024711

=2.20548

=0.3435031

=0-2200967

Lbs. per square inch in 1 kilogramme per square millimètre =1422
Cwts. ditto, ditto

=12.7

Grains in a cubic inch of distilled water, Bar. 30 in., Th. 62° =252-458
Cubic inches in an ounce of water

Cubic inches in the imperial gallon

Feet in a geographical mile

Log. of ditto.

=1.73298

=277.276

=6075.6

=3.7835892

To find the weight in lbs. of 1 foot of common rope, multi

ply the square of its circumference in inches by Ditto for a cable

Note.-The numerical values of the function of in this table were calcu lated by Mr. Goodwin. These, together with the numbers of cubic inches and feet per cwt. or ton of different materials, are taken from the late Dr. Gregory's excellent treatise, entitled Mechanics for Practical Men. The other numbers of the table are principally taken from Mr. Babbage's Tables of Logarithms and the Aide Mémoire of M. Morin.

044 to 046 ⚫027

THE END.