650 REPORT—1883. 
since the introduction of steel as a material; and its advantages, so far as stiffness. 
is concerned, have been lately set forth in a paper by Professor Greenhill (‘ Proceed- 
ings Inst. Mech. Engineers,’ April 1883). In the discussion on that paper, how- 
ever, Mr. Edward Reynolds, of Sheffield, quoted some experiments made by him 
on hollow and solid shafts under the impact test, in which the hollow shaft was 
much the inferior of the two, and gave way very rapidly when once the strain 
exceeded a certain limit. This is exactly what the theory now given points out 
would be the case. 
It would seem, therefore, that the provision of hollow shafts is a serious error 
in all such cases, and should not be continued. 
SATURDAY, SEPTEMBER 22. 
The Section did not meet. 
MONDAY, SEPTEMBER 24. 
The following Report and Papers were read :— 
1. Report of the Committee on Screw Gauges.—See Reports, p. 318. 
2. On Nest Gearing. 
By Professor Fizemina Jenkin, F'.R.S.—See Reports, p. 387. 
3. On Telegraphic Intercommunication. By W. H. Prexce, IRS. 
The ABC telegraph of Wheatstone was used in 1864 in Newcastle, and an 
Exchange formed there to facilitate intercommunication among the subscribers. 
In 1882 the ABO apparatus was replaced by telephone, and a great impetus given 
to this mode of transacting business. All the outlying manufacturing district was 
brought into the system. The wires are placed underground, and are used in 
metallic cireuit. The Gower-Bell form of telephone is that used. A special form of 
switch board has been designed by which prompt attention is secured, by which the 
switch clerk can see at a glance the condition of every wire, whether it is engaged 
or not, and whether the subscriber is in his office or not. There are over 330 
subscribers. The average number of telegrams dealt with daily is 210, and the 
number of exchanges of intercommunication 2,200. 
The system now embraces Newcastle, Sunderland, South Shields, Tyne Docks,. 
West Hartlepool, and Middlesbrough. 
4, On Electric Launches. By A. RECKENZAUN. 
The paper commenced with a description of the launch ‘ Electricity,’ which 
made her first trip in September 1882. 
The ‘ Electricity’ is 25 feet long, with a 5 feet beam, and draws 2] inches 
forward and 30 inches aft, Her speed is 8°3 miles per hour with ten passengers 
on board. Forty-five Sellon-Volckmar accumulators stored under the seats and 
decks forward and aft supplied the current to two Siemens D, Series dynamos. 
ae side by side on the floor of the boat, with their axes parallel to the propeller 
shait. 
