426 



REPORT— 1897. 



Results of Tensile Tests made with Rod B. 



Width 

 Thickness . 

 Section 



Measured Length 

 Elongation- measurer 

 Machine . 

 Temperature of room 



Load P. 



Kilos 



5470 



5080 



7620 



10160 



12700 



Average 



2540 



h = 50'4 millimetres. 



<Z=12-9 millimetres. 



F — 650'2 square millimetres. 



L = 100 millimetres. 



Martens' Mirror Apparatus. 



Werder's System. 



t = n° Centio-rade. 



Increment of Elongation in O'OOOl mm. for every 2,540 

 kilo3. 



In series of experiments 



192 



189 

 190 

 190 



190-3 



±0 



192 

 190 

 192 



188 



190-5 



+ 2 



192 

 185 

 191 

 191 



189-8 



±0 



192 

 191 



188 

 192 



190-8 



+ 1 



191 

 189 

 191 



188 



189-8 



±0 



Average 



191-8 



188-8 

 190-4 

 189-8 



190-2 



Residual 

 readings 

 on tak- 

 ing off 

 the load 



Remarks 



05 

 JO 

 O 



II 



O 



a 

 a 



<» s 



w 



^ a 

 '0 ^ 



Screw Gmige. — Second Report of the Committee, consisting of Mr. 

 W. H. Pkeece {Chairman), Lord Kelvin, Sir F. J. Bramwell, 

 Sir H. Trueman Wood, Major-Gen. Webber, Col. Watkin, Messrs. 

 Conrad W. Cooke, E. E. Crompton, A. Stroh, A. Le Neve 

 Foster, C. J. Hewitt, G. K. B. Elphinstone, T. Buckney, 

 E. EiGG, and W. A. Price (Secretarif), appointed to consider 

 m,eans hy ivhich Practical Effect can he given to the Introduction 

 of the Screw Gauge p>roposed by the Association in 1884. 



At the meeting in Liverpool in 1896 your Committee reported that 

 sufficiently accurate gauges of the British Association screw threads -were 

 not generally procui-able. They described methods of exactly measuring 

 male threads, and proposed a form of gauge for male threads -which they 

 anticipated could be more accurately produced, and more easily verified 

 than the forms in common use. 



In continuation of this course they have been in correspondence with 

 some of the principal tool-makers in England and America, with a view 

 to procuring accurate gauges of the different screw threads of the British 

 Association system constructed on the lines indicated in their last 

 report. 



The Pratt and Whitney Company of Hartford, Connecticut, had 

 already begun to construct tools for these threads, when the Secretary of 

 the Committee wrote to them, and are giving close attention to their 

 accurate production. The Company have kindly promised to communicate 

 ■with the Committee as soon as the work is sufficiently advanced to allow 



