AND ITS APPLICATION TO MR. B. TOWER'S EXPERIMENTS. 
207 
These theoretical results will be further discussed in Section IX., where they will 
be compared with Mr. Tower’s experiments. 
29a. c=‘h is the limit to this Method of Integrating. 
In the case considered, in which 6=78 c SI' 20”, Table II., shows that the pressure 
towards the extreme offside is just becoming negative. With greater values of c this 
negative pressure would increase according to the theory. 
The possibility of this negative pressure would depend on whether or not the 
extreme off edge of the brass was completely drowned in the oil bath, a condition not 
generally fulfilled, and even then it is doubtful to what extent the negative pressure 
would hold, probably not with certainty below that of the atmosphere. 
With an arc of contact anything like that of the case considered it would be neces¬ 
sary, in order to proceed to larger values of c than 5, that the limits between which 
the equations have been integrated would have to be changed from 
— #i, -\-6 x , 
to 
2 ) ^*1’ + ^i- 
This integration has not been attempted, partly because it only applies, in the case 
of complete lubrication, when the value of c. > ’5 renders approximation very laborious, 
but chiefly because it appears almost obvious that the value of c, which renders the 
pressure negative at the off extremity of the brass is the largest value of c under 
which lubrication can be considered certain. 
The journal may run with considerably higher values of c, the continuity of the film 
being maintained by the pressure of the atmosphere, which would be most likely to be 
the case with high speeds. But although the load which makes c = ‘5 is not neces¬ 
sarily the limit of carrying power of the journal, it would seem to be the limit of the 
safe working load, a conclusion which, as will appear on considering Mr. Tower’s 
experiments, seems to be in accordance with experience. 
This concludes the hydro-mechanical theory of lubrication so far as it has been 
carried in this investigation. There remain, however, physical considerations as to 
the effect of variations of the speed and load on a and p. which have to be taken into 
account before applying the theory. 
