474 



Scientific Proceedings^ Royal Dublin Society. 



about 2 c.cms., hence, in recording the maximum pressure, the bean is 

 allowed to swell less than -^-^ of the amount it would expand under free 

 conditions. By leaving on an initial pressure of 2 atmospheres tlie possible 

 expansion is reduced to less than j-'-g. 



It is C[uite possible that the expansion permitted to the seed may be 

 greater than the estimated value, since there may be a certain amount of 

 compression of the sand.' It is proposed to carry out experiments to 

 determine the compressibility of sand under tlie pressures involved. 



We give below four examples of records obtained with this instrument ; 

 the seeds tested were broad beans, variety Milecross Monarch. The figures 

 are given in Table I. Fig. 3 shows the same results as curves. 



Hours. 

 Fig. 3. 



These results are given with certain reservations. They are intended to 

 indicate the nature of the records obtainable by the apparatus rather than 

 exact measurements of tlie pressures of the seeds, as corrections of variations in 

 temperature and barometric pressures were not made. 



' Due to fracture of grain and consequent closer packing, rather than to actual compression of the 

 and particles. 



