60 SEC. 3. MEASUREMENT. 



To use the instrument it is merely necessary to advance it along the object 

 to be measured, when the large hand will register the inches and fractions of 

 an inch on the outer dial, the smaller hand on the inner dial, the feet and the 

 smallest hand on the recessed dial, the tens of feet travelled over. The in- 

 strument registers to 100 feet. Price, electro-silver, in leather case, 16s. &d. 



277a. Pedometer, of the latest and most approved form. 



J. and W. E. Archbutt, Westminster. 



This instrument has pendulum action, and is worn suspended in the waist- 

 coat pocket ; it is provided with a regulator whereby it can be set to most 

 accurately record distances walked. 



277b. Improved form of Pedometer, by Dolland, in which 

 the direct chain action is substituted for the lever made in the early 

 part of the nineteenth century. 



J. and W. E. Archbutt, Westminster. 



277c. Pedometer or instrument for accurately register- 

 ing distances walked. This instrument was invented and made 

 by Spencer and Perkins in tfre latter part of the eighteenth 

 century. J. and W. E. Archbutt) Westminster. 



278. The Chart ometer. E. Russell Morris's patent. (Silver 

 Medal, awarded at Manchester, 1875.) 



The Morris Patents Engineering Works, Birmingham. 



The only instrument that measures and registers distances on maps, plans, 

 scaled drawings, &c., and that is adapted for various scales. By guiding the 

 small steel wheel along any route on a map, the hand registers the actual dis- 

 tance in miles, yards, &c., according to the dial in use and the scale of the 

 map, which should correspond. To deal with a map of a difficult scale, the 

 glass front is opened by pressing a spring ; the dial removed, and another 

 corresponding to the fresh scale slipped into its place. A set of dials adopted 

 to the scales of all the Ordnance maps, and the usual scales of travelling 

 maps, &c., &c., is contained in a recess of the leather case, beneath the 

 instrument. 



290. Scale for Measuring Curves. Eschenauer's patent. 



Hermann Schafer, Darmstadt. 



1093a. Ellipsometer. 



Before the eye-piece of the glass, a double refracting prism is made to turn 

 until a wire, moving perpendicularly to the principal section of the prism, 

 gets to pass through the two intersecting points of the two reflections of the 

 ellipse. An index shows at the moment the position of the prism. 



III. MEASUREMENT OF AREA. 



316. Amsler's Planimeter, for calculating with perfect 

 accuracy the contents of plans, maps, or other plane surfaces, in 

 square inches and metrical measure. Elliott Brothers. 



