OX A GAUGE FOR SMALL SCREWS. 293 



screws, international in its character, English mannfacturers of screws, 

 screw-plates, &c, adopt the exact pitches given in millimetres in Colnmn 

 VI., which, as explained in par. 9, can, if required, be originated on an 

 English lathe. Further, in view of the fact that small screws and screw- 

 plates, while nominally alike, will not unfrequently differ considerably as 

 regards their number of threads per inch, the practice of designating such 

 screws by their number of threads per inch should not be adopted. For 

 reference, however, the approximate number of threads per inch, as 

 calculated from the pitch given in Column VI., are given in Column IV. 



(4) That the designating numbers given in Column I., being the indices 

 of the powers to which 09 is raised to obtain the pitch, be punched against 

 each hole in the screw-plate, aud that, if thought desirable, its diameter in 

 thousandths of an inch (Column II.) might be punched side by side with 

 this number. 



2o. In his Syslematique des vis Horlogeres, Prof. Thury has done for 

 the small screws used by watch, clock, and scientific instrument makers 

 what was done forty years ago by Sir J. Whitworth for the larger screws 

 used by engineers ; and, like the admirable system introduced by the 

 latter, the scheme here advocated is based on the data obtained by measur- 

 ing the several dimensions of many screws accepted by practical men 

 as being well-proportioned. 



26. The Committee has had an opportunity of examining both screws 

 and screw-plates (for the smaller screws) made on this system, which it is 

 convinced will satisfy all the demands of practice. The Committee can, 

 therefore, confidently recommend its adoption by the British Association, 

 subject to the slight modification discussed in par. 23 ; and it feels that an 

 important incidental advantage would be the support it would at once 

 receive on the Continent, and the consequent increased rapidity with 

 which it might be expected to come into general use ; for it cannot be 

 doubted that its recognition by so important a body as the British Asso- 

 ciation would have considerable influence in establishing the system 

 abroad. 



[The recommendation for the appointment of this Committee having 

 failed to reach the Committee of Recommendations at Southport in time 

 to allow of its sanction by the General Committee, the Council at their 

 meeting on November 6, 1883, requested the Committee to continue their 

 labours, and undertook to recommend to the General Committee at 

 Montreal that this Report be printed among the Reports.] 



Report of the Committee, consisting of Sir Frederick Bramwell 

 (Secretary), Professor A. W. Williamson, Professor Sir William 

 Thomson, ]\Lr. St. John Vincent Day, Sir F. Abel, Captain Doug- 

 las Galton, Mr. E. H. Carbutt, Mr. Macrory, Mr. H. Trueman 

 Wood, Mr. W. H. Barlow, Mr. A. T. Atchison, Mr. R. E. Web- 

 ster, Mr. A. Carpmael, Sir John Lubbock, Mr. Theodore Aston, 

 and Mr. James Brunlees, appointed for the purpose of watching 

 and reporting to the Council on Patent Legislation. 



The Act for the reform of the Patent Laws, passed in 1884, having 

 only come into operation in January of the present year, sufficient time 

 has not yet elapsed for its working to be tested. The Committee, there- 



