2Q2 THE SCIENTIFIC PAPERS OF 



velocity by friction in the dram. This loss may be taken to 

 represent with tolerable accuracy the degree of obstruction opposed 

 by the meter to the moving water column. The rapid current of 

 the water through the inlet E and the curvilinear channels of the 

 drum has been found to prevent deposit of calcareous matter in 

 these places, which is an important point, for were it otherwise, 

 the meter would gain in relative speed in proportion as the area of 

 the channels was diminished. 



Meters constructed on this plan have now been found to work 

 continuously for nearly three years under the most varied circum- 

 stances without requiring any alteration whatever. The arrange- 

 ment made between the manufacturers and the water companies 

 or purchasers of the meters is that every meter that fails to give 

 satisfaction, in consequence of stoppage or inaccuracy of measure- 

 ment, shall be exchanged ; and experience shows that the number 

 of meters so returned does not exceed 2j per cent, in the year, 

 and these for the most part have been sent back only from trivial 

 causes. The more serious accidents have been that the meter has 

 become choked with gravel or other impurities, that had entered 

 through a broken grating ; or that the regulating vanes have 

 been broken, and the relative velocity of the revolving drum has 

 been much increased ; or that some derangement in the wheel 

 work of the counting apparatus has taken place. In winter it has 

 happened that the casing of the meter has been burst by frost, but 

 this class of accidents' does not concern the mechanical arrange- 

 ments of the meter. The manufacturers enter into contracts to 

 maintain the meters supplied by them in good working condition 

 for a term of years, in consideration of the moderate annual charge 

 of 5 per cent, per annum on the first cost, proving thereby their 

 own confidence in the durability of the meters. 



A further object of this paper is to prove from actual experi- 

 ence the utility of the meter to water companies and water con- 

 sumers, and to engineers and others for general purposes. 



Although the meter has been as yet but partially applied by 

 water companies as the arbiter between themselves and their 

 irregular or trade customers, the advantages to the companies 

 from prevention of waste, error, and fraud, have been made 

 manifest. The following Table gives the results of the applica- 

 tion of fifteen meters, showing the difference between the rate paid 



