TIMBERS. 341 
was indicated on a dial fixed above the beam, and having a point 
connected by a simple arrangement with the iron staple to which 
the scale was attached), were recorded as those at which the 
elasticity had become impaired, and used as the necessary factors 
for determining the value of E. After this, successive additions 
were made of half a cwt. at the intervals and in the manner already 
mentioned, until the beam broke; the breaking weight, or that 
less by half a cwt., if the beam broke within one minute of the 
weight being applied, being taken to determine the value of the 
constant S. 
“The screw-jack employed was found convenient for many 
purposes. Being fitted on the top with a horizontal table, it 
served to raise and lower the scale containing the weights, and 
thus to apply to the beam the desired pressure without jerk ; it 
admitted of such an adjustment of the table as to prevent (on the 
fracture of the beam) the fall of the scale through unnecessary 
space, and the damage to the scale often so occasioned ; and it 
allowed the scale to be attached to a fresh beam without removing 
the whole of the weights.” 
1865. ‘Results of a series of experiments on the strength of 
New Zealand and other colonial woods, by J. M. Balfour, C.E., 
Provincial Marine Engineer of Otago, etc.” Forming Appendix 
C of the Report of the New Zealand Exhibition of 1864. 
The experiments were conducted in the following manner :— 
“A pressure of solbs. was applied for two minutes (as 
measured by a sand-glass), and the sample was then released; 
75lbs. were then applied for the same time; then a 1oolbs., and 
sO on, increasing by 25lbs. each time. Each time the sample was 
released the point on the deflection scale to which it returned was 
read, and when it came to be notably under the original reading, 
the specimen was allowed to remain unloaded for two minutes, to 
see whether it would in time further recover itself. When, how- 
ever, there were indications that the point of fracture was nearly 
attained, the pressure was gradually and steadily increased, with- 
out being again removed, until the specimen broke, the observer 
keeping his eye on the deflection scale and noting its reading at 
the first crack, the maximum pressure exerted being indicated on 
