CATALOG OF THE MECHANICAL COLLECTIONS Ql 



McNAUGHT INDICATOR, c. 1835-1842 



PlATB 20, FiGUEE 1 



"U.S.N.M. no. 307516; original; gift of tlie Ball Engine Co.; photograph no. 

 15260A (group). 



This is an original indicator made by the old Novelty Iron Works, of 

 New York City. Marked "Novelty Iron Works, New York, No. 4." 



This indicator is one of the first type to employ a cylindrical 

 drum to carry the paper, in place of the flat board of the Watt in- 

 dicator. This feature was the invention of John McNaught, of 

 Glasgow, Scotland, who introduced an indicator with this improve- 

 ment about 1825-1830. 



The indicator consists of a vertical cylinder and a closely fitted! 

 piston with a helical spring between the piston and the cap at the 

 upper end of the cylinder. A piston rod projects beyond the top 

 of the cylinder, as in the Watt indicator, but in this case the pencil 

 is attached to the rod just above the piston. The fitting that car- 

 ries the pencil slides in a vertical slot provided for it in the wall of 

 the cylinder. A hollow metal drum is supported on a bracket close 

 to and parallel with the cylinder. A spring on the pencil fitting 

 presses the pencil against the surface of the drum (in some of the 

 earlier models the paper was cemented to the drum). The paper 

 drum is revolved by a cord wrapped al)out the base of the drum and 

 is returned by a light coil spring within the drum. The piston 

 rod extends beyond the top of the cylinder and is fitted with a 

 small knurled nut so that an additional spring can be added for 

 higher pressures. A scale is marked off along the edge of the slot 

 in which the pencil fitting moves so that pressures may be read 

 directly when the indicator is used with a slow-moving engine. 



KRAUSCH ENGINE INDICATOR, 1862 



U.S.N.M. no. 308664 : original patent model ; transferred from the United States 

 Patent OflSce ; not Illustrated. 



This model was submitted with the application for the patent 

 issued to C. W. T. Krausch, of Chicago, 111., September 9, 1862, 

 no. 36411. 



The model represents an instrument designed to indicate and 

 record speeds, draw-bar loads, boiler water levels, boiler pressures, 

 steam-chest pressures, cylinder pressures, and conditions of the track 

 connected with the operation of a locomotive engine and to plot 

 these on a paper belt driven from a truck axle with a motion cor- 

 responding to the progress of the engine. 



A series of levers and markers corresponding to the number of 

 the above operations to be recorded works transversely on the paper 

 record as the paper is advanced by the progress of the engine. The 



