364 Mr. Malum' i Gas-Meter. 



meter has been proved in the most satisfactory manner upon the 

 Westminster gas-works. I therefore take tlie liberty of re- 

 questing you will have the goodness to let the meter now sent be 

 brought before the Society of Arts for its consideritiion. The 

 meter herewith sent being one for actual use, I am now prej/aring 

 a model of the same dimensions, partly constructed of glass so 

 as clearly to exhibit its operation ; ?.nd to the model alluded to, 

 I have also attached a dial, and the necessary U'heel-work for 

 pointing out the number of revolutions, and consequently the 

 quantity of gas passing through it in any specified time for sup- 

 plying one or more burners, which I shall be most happy to pre- 

 sent to the Society on receiving their con)mands for my doing so. 



I am, sir, &c. 

 A. Aikin, Esq. Secretary, &c. John Malam. 



References io the Engravings, Plate III. 



Fig. 1 is a section across the axis of the machine. 



Fig. 2 is a section thrcugh the axis. 



A A is the outer case of the gas-meter, within which the in- 

 terior cylinder B B revolves upon the pivots yz. The former of 

 these pivots is attached to the inverted pipeDD, which brings 

 the gas into the central chamber E. Hence it is conveyed by the 

 openings a, h, c, d, into the compartments or cells B, K, G, H, 

 in rotation, as each of them rises above the level of the water a:x. 

 The gas is then discharged into the cuter case by the openings 

 1, 2, 3, 4, from which it passes into the regulator by the pipe L. 



M M is the outer case of the regulator which is kept full of 

 water; NN is the inner vessel, attached to the exterior one by 

 the hinge ff, so as to allow this part with the cone g to rise 

 and fall freely. 



O is the pipe which conveys the gas into the interior vessel. 



P is the e>fit pipe which transurits the gas to tiie burners. 



Fig. 3 is a cross section of the valve ; tlie use of which is to 

 prevent any gas from passing into the meter, unless a sufficient 

 quantity of water is in the instrument. 



R is the inlet pipe to the partition, i the cnp, kk the float, 

 // the clip-pipe which carries off the superfluous water that 

 would otherwise run over through the inverted pipe D till it had 

 attained its level. 



Fig. 4 is the dial and pointer which is secured by a strong 

 glass in a brass ring being soldered over it. 



Fig. 5 is a se^t'on of the counter, showing the wheels and stop. 



Fig. fi is a section of the lever and crank in the trough. 



Fig. 7 is a cross section of the crank, the lever, the trough, 

 the wheels, dial and pointer. 



The use of the counter is, to register the number of revolu- 

 tion* 



