. 55242. 



Mechanical Equivalent of Heat. Heat Engines. 



629 



55 241. 1 : 4. 



52,228. Apparatus after Christiansen for determining the Mechanical Equivalent of Heat, (1 

 F i g u r e (M. P., Ill, Fig. 407 [II, 2, Fig. 255]; W. u. E. phys. Prakt., Fig. 121), with 

 110 volt D. C. motor, the accuracy of the apparatus is about 1% 16. 0.0 



55,230. Apparatus after Callendar, Figure, for determining the Mechanical Equivalent 



Of Heat, driven by a 110 volt D. C. Motor. 1 Including motor 16. 0. 



The work of friction is generated by loaded silk brake bands laid round a rotating cylinder of thin 

 luass filled with a certain quantity of water. The heat is measured by a thermometer introduced 

 through a central aperture into one of the cylinder bases. The number of revolutions is indicated 

 by a speed connter. Thermal loss can be eliminated by Rumford's compensation method by two 

 measurements with different load. The lecturer can obtain values accurate to approx. */s% in the 

 presence of the audience within 10 minutes. 



.V>. 231. -- idem, for working by hand, without motor 12.10.0 



.V..232. Apparatus after Joule, Figs. A and B, for determining the Mechanical Equivalent 

 Of Heat (M. P., Ill, Figs. 404/5 [II, 2, Figs. 252/3]; Gan.-Man., Fig. 517; Gan.-Bein., 

 Fig. 462), with Wood Stand and vertical rules |l6. 0.0 



Heat Engines. 



Hot Air Engines with Ribbed Cooler. F i g. 55,234. 



List Xo. 55,233 55,234 55,235 55,236 55,237 55,238 55,239 55,240 



Piston Diamr., . mm 30 

 Flywheel Diamr., mm 118 

 Efficiency ... HP V, M 



(a) Spirit-heated . 1. 16. 



(b) Gas-heated . . t 



(c) Petroleum-heated 



100 

 410 



V, 



18. 10. 



17. 10. 33. 10. 41. 0. 



19. 10. 37, 0. 45. 0. 



130 

 550 

 V* 



150 

 590 



91 



This hot-air engine forms a very simple, cheap and safe motor. The ribbed cooling replaces the 

 water-cooling adopted in other hot-air engines and their attendant disadvantages and simplifies the 

 manipulation of the motor in that it is only necessary to light the heating jet spirit, gas, petroleum 

 or petrol for starting. 





55,241. Instructional Model of a Gas Engine after Eichter, Figure (Ztschr. f. d. phys. 

 u. chem. U., 12, 1899 p. 265) 



3. 4.0 



The model explains the mode of action of a 4-cycle gas engine. The four cycles of the motion 

 of the piston, also Ignition and gearing can easily be explained. It is possible to set the model in motion 

 (it cannot be worked) by a handle fixed to the flywheel. 



55,242. Model of a Horizontal Gas Engine, Otto system, 1 / 10 HP; see Fig. 55,243, p. 630, 



working as a 4-cycle motor with electric ignition, for house gas or petrol 18. 0. 



Dimensions: bore 50 mm, flywheel diam. 400 mm, speed 800 r.p.m., gas-consumption 300 litres 

 per hour. The following pertain to the engine: 1 gas bag, 1 cooling vessel, 1 ignition coil, 1 double 

 cell, o leads, 2 spanners. 



1 With motor working at other current or voltage at corresponding variation in price. When ordering, 

 pe of current and voltage should be mentioned, and in the case of 3-phase current, the frequency. 



Cl. 1887. 



