45, CORNHILL, E.U., AND 122, REGENT STREET, W., LONDON. 



297 



FIG. 1185. 



1185 Perambulator, for measuring the length of roads, streets, &c., consists of an 

 accurately framed Mahogany Wheel, Brass Clamped, the circumference 

 of which is carefully ascertained ; the axis of this Wheel is connected 

 by a series of toothed wheels and pinions to a dial, upon which the number 

 of revolutions of the Wheel are recorded. The divisions upon the dial are 

 English^ Measures ; but any Foreign scale can be substituted to order. 

 Price, Best mounted and finished (fig. 1185) . . . 16 16 



FIG. 1186. 



FIG. 1190. 



1186 



1187 



Trocheameter, Negretti and Zambra's Improved construction for 

 registering the revolutions of a Carriage Wheel and by this ascertaining 

 distances travelled ; it is also applicable for counting the revolutions of fly 

 wheels, paddle wheels, &c., up to 10,000 revolutions, or nearly 23 miles 

 distance, travelled by a coach wheel of 12 feet circumference. These 

 numbers can be repeated by re- setting the instrument, which is very easily 

 done, by removing a nut, and turning back the divided wheels to the 

 point. The Trocheameter is contained in a strong case, with a 

 leather strap for attaching it to the wheel, &c. (fig. 1186) . 330 



The Dipleidescope.f A Pocket instrument for obtaining the 

 Correct Time with great facility, by observing the Transit of the 

 Sun across the Meridian * best form 10 10 



t See also N. & Z's. Improved Transit Instruments, page 254. 



