Proceedings, &c, for 1885. 165 



Mr. Ellery's opinion was that, though as a general rule, it is not 

 a good rule that one person should be President of the Society 

 and Chairman of one of its sections, yet, in view of the strong 

 feeling expressed by the members for Professor Kernot to retain 

 the chair, he thought in this case it was permissible. Acting on 

 this advice he would continue as chairman for the present, but he 

 hoped to see some other member fill the place as soon as a fit 

 opportunity should arise. 



Three papers were before the meeting. 



(1.) One by Mr. M'Lean, on "Long Shafting." Postponed from 

 the last meeting. 



(2.) One by Mr. G. E. B. Steane, on " Rainfall and Flood Dis- 

 charge." 



Mr. Steane was absent, on account of a death in his family, and 

 asked that his paper might be postponed. This was accordingly 

 done. 



(3.) Mr. L. H. Chase, on " Sewage Systems." 



The first paper read was Mr. C. W. M'Lean's, on "Long 

 Shafting." 



The operation, of ranging long lines of shafting is usually effected 

 by means of a piano wire about 100 feet long, strained tight. But 

 this method is open to one great disadvantage — the sag. Taking 

 resistance to tearing at 100,000 lbs. per square inch, and weight 

 equal to *26 lbs. per cubic inch, we can see that if this could 

 be strained up to the point of rupture without yielding, the sag 

 would be about J inch. The operator estimates the true line, and 

 places the bearings accordingly. Of course this method, with 

 ordinary care, will give the horizontal direction close enough. 

 The importance of having the line very accurate would seem to be 

 great, for it is invariably found that in carelessly-laid work either 

 the shaft heats or else the couplings or the crank break. The first 

 departure from this practice seems to have been the use of a disc 

 and tube, though this is not perfect on account of the obstruction 

 of light at the slit in the tube. A short time ago Mr. M'Lean was 

 called on to examine some long shafting, which was working very 

 badly ; and to do this more perfectly than could be done by the 

 old system, he devised the following method : — 



In the case under notice the couplings were all of one size, but 

 a similar method could be applied in any case. He placed a 

 telescope having crosswires on one of the end couplings, and held 

 it in place by a small block of wood as a carrier, and a weighted 

 string passing over the whole. A small scale was then placed 

 vertically on the other end coupling, and the reading taken, and 

 the process repeated at each intermediate coupling piece. The 

 comparison of the results showed an error of about \ in. at one 

 end. The soleplate was planed down by this amount, the shaft- 

 ing readjusted, and the result has been perfectly satisfactory. 



