22 HISTORICAL SKETCH OF THE 



were then tried ; but they also became stiffened and useless in a very few 

 months. Recourse was then had to two small gasometers, filling and work- 

 ing them alternately, in the same manner as the bladders ; but the lights were 

 so unsteady, that the intervention of a gasometer was necessary between them 

 and the meter, which took up much room and was expensive. One of these 

 meters was erected at Mr. Ackerman's, in the Strand, and another at Mr. 

 White's, in Abingdon Street. The next meter was in the form of a concen- 

 tric cylinder, divided into three chambers, revolving upon an axis in a tank, 

 the water reaching to within a short distance of the axis, the remaining part of 

 the machine being in the open air ; the gas entered at one end of the axis, 

 which was hollow, and was discharged at the other end ; the entrances to the 

 different chambers were opened and closed by mercury contained in complicated 

 scrolls, far too delicate in their construction to render it a generally useful 

 machine. The third alteration in form was to divide the vessel into two 

 chambers, and to enclose the meter entirely in a case containing water at the 

 bottom, into which the measured gas was discharged ; the mercurial scrolls 

 were done away with ; the bent siphon tubes, which partly filled with water 

 as the meter revolved and alternately opened and shut off the communication 

 between the hollow axis and the chamber, were alone retained : this axis 

 worked with considerable friction and rendered the meter still very imperfect. 

 The merit of applying a pipe on one side of the axis, to convey the gas into 

 the meter, is due to Mr. Malam, decidedly the most important improvement 

 since its invention ; from this time the machine was gradually improved, finally 

 rendered perfect, and brought into general use by Mr. Crosley. The im- 

 perfections under which the meters labour, are rapid decay from exposure to 

 the influence of water, the variation of the water-line, freezing, and the press- 

 ure required to work them. The former of these have been in some degree 

 remedied by Mr. Hemmings, in what he calls his Patent Protector gas-meter, 

 to what extent, remains yet to be proved ; but the last disadvantage can never 

 be removed, owing to mechanical difficulties, which it is impossible in its 

 present form to surmount. 



Within the last few years a patent has been taken out for a Dry Gas-meter, 

 upon precisely the same principle of action as that adopted by Mr. Clegg in 

 the first instance, which he was obliged to lay aside, both on account of 

 defects in the material of which the meter was formed, and of the unsteady 

 motion it gave the lamps when immediately connected with them. The Dry 



