2 SEC. 1. ARITHMETIC. 



7. Slide Rule, of ivory, adapted for use in iron and steel plate 

 and sheet rolling mills. Aston Mander. 



This rule will show directly the precise net and waste weight of iron and 

 steel plates, and sheets, of any size, shape, and thickness. It may be applied 

 to all ordinary metals, and to find areas, cubic contents, liquid capacity, &c. 



8. Slide Rule, of boxwood, adapted for sheet iron and steel 

 manufacturers. The dimensions, thicknesses, a^pd weights are 

 given both in English and metrical standards. 



Aston fy Mander. 



The length of the sheet or plate (on the slide) being first set to the width, 

 then immediately below any thickness (on the top lines) will be found (on 

 the slide) the actual weight of the sheet either in pounds (avoirdupois) or 

 kilogrammes. 



9. Slide Rule, of ivory, adapted for use in iron and steel-bar 

 rolling mills, showing instantly the precise net and waste weights 

 for bars of any length, size, and form. Aston $ Mander. 



9a. Three Slide Rules. Elliott Brothers. 



10. Estimator. A sliding rule, by which the volume of 

 prismoidal bodies (embankments, ditches, cuttings, &c., occurring 

 in the construction of railroads, canals, fortifications, &c.,) is cal- 

 culated mechanically. 



Dr. F. M. Stapff, Geological and Mining Engineer at the 

 St. Gotthard Railway. 



This instrument, invented by the exhibitor, is patented in Sweden and the 

 United States of America. 



11. Set of Gauging Instruments. Dring and Fage. 



Head rod. For ascertaining the head diameter of a cask, and working out 

 the contents. 



Bung rod and slide. For finding the bung diameter and diagonal of a cask. 

 The rod is divided into inches and tenths, with a line of imperial area and 

 diagonal line ; this last gives the approximate content without calculation, 

 and is computed on the assumption that most casks are similar to one another 

 in form, and therefore vary as the cubes of their like dimension. 



Long callipers used for finding the internal length of a cask from head to 

 head. 



Cross calliper. Used for finding the external diameter of a cask. 



Stave gauge. For finding the thickness of the stave in a cask. 



lla. A Timber Rule, for finding the content of timber of 

 any form, regular or irregular. The rule has eight gauge points 

 or divisors for reducing dimensions in inches to contents in square 

 feet. Dring and Fage. 



lib. " Verie" or Excise Officer's Rule. 



Dring and Fage. 



