2 SEC. 1. ARITHMETIC. 



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

 and sheet rolling mills. Designed by Okas. Hoare. 



Aston Sf 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 boxAvood, adapted for sheet iron and steel 

 manufacturers. The dimensions, thicknesses, and weights are 

 given both in English and metrical standards. Designed by 

 Chas. Hoare. 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, metrical Or English measures being used without previous 

 conversion. 



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. Designed by Chas. Hoare. 



Aston $ Mander. 



24. Scales, of boxwood, to show cubes, squares, and roots, 

 areas, diameters, circumferences, and decimal equivalents. De- 

 signed by Chas. Hoare. Aston $ Mander. 



The bevel edged set square is used to read the divisions, and dispenses with 

 the need of voluminous printed tables. 



9a. Three Slide Rules. Elliott Brothers. 



10. Estimator. A slide 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. 



lla. 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 Page. 



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



Dring and Page. 



Verie is probably a corruption of " Vero," a revenue officer who made an 

 alteration in the method of laying down some of the lines on the rule ; 

 previously to which they were called Everard's rules. 



