ny a 
ht. FE. Browne—Becker’s Theory of Faulting. 349 
stock, applies to it with much precision. Equations can be 
given representing very closely the surface line se a cross-sec- 
tion, the amount of the fault can re determined, e 
e above quotations from the summary, pp. 376- 380, are 
made in order to bring before the reader, as briefly as such 
means will permit, some > of the prominent features of the theory 
which it is proposed to criticise. 
In the discussion under the several headings, ‘“ Transmission 
of energy by friction,” “Distribution of energy through a sys- 
the 
tem of sheets,” “The velocities of moving sheet, ete,’ ere 
appears a misconception of an aed ates question involved. 
Mr. Becker says if sheet W (see fig. 1) “begins its motion 
With a fixed quantity of energy, and if P, is fixed, the entire 
W will be communicated to P,, 
ou. * 
These statements are true, but 
it must be borne in mind, that in 
effect, the force of friction. is 
simply a resistance to relative 
psc If P, offers greater 
sistance to a felative move- 
ment of W than the body of ies to the rivht offers to a 
iy movement of P,, it follows that relative rest between 
P, will not be disturbed, and the latter will move with 
the: “fall velocity of the form er.t is initially at rest, it 
will either remain at rest or eacuits the full ed of W. 
is in contact with a third plate or sheet P, the energy 
received by P, will be expended wholly or in pat in overcom- 
ing the resistance on the contact P, P».” It sho be kept in 
view that if P, moves at all, it does so with the fall velocity of 
P,, for the reasons above given. “If these sheets are the earlier 
* The pressure exerted by W upon P,, was considered as uniformly distributed 
—see * page 35 
This statement apparently calls for some quslifeaticn, for if a considerable 
Velocity is suc Idenly imparted to W, and the resistance m entioned means wary 4 
frictional resistance, the inertia of P, will give rise to a diblocetion at contact 
1 towever, if the most reasonable conditi i 
of W is s supposed to be small, and there is assumed to be a material diff 
tween the frictional resistance which P, offers to motion of W a 
body of the sheet to the right offers to motion of P,—it is proper to consider that 
f P, offe i ation, 
the resistance which the mass 0 srs nn eelion will not cause dislocé 
but will result in Hose cre in the elastic sheets transmitted through the projec- 
tions at the contact. It ot supposed that it was M r's intention to con- 
Sider any appreciable valet ity as being suddenly acquired. e “fixed ity 
of energy,” with which W begins its motion, cannot be energy of motion ‘icinetic 
=8)) 
ergy). » 
