
Figure 6.—CRross-SECTIONAL VIEW of the original Ellis 
(USNM cat. no. 317669.) 
current meter. 
using inverted cup bearings, which would trap air, I 
could exclude the water and grit. I made drawings for 
such a meter that night, and by employing four mechanics, 
the meter was completed the next day at 3 p.m. 
This meter was used for measuring the great flood of 
that year, 1882. 
In other documents, Price revealed that in the group 
of mechanics he had hired, one was a tinsmith, another 
a blacksmith, and a third a locksmith. They were 
‘The actual current 
meter constructed on that occasion is shown in 
figure 2. 
‘the best mechanics in town.” 
Price’s criticism of the Herschel current meter was 
thoroughly justified. Three types of these meters are 
shown in figure 5. The impellers, which consist of 
four fan-shaped blades surrounded by a circular 
metal band, are likely to catch submerged grasses 
and leaves which inevitably impede its normal rotat- 
ing action, and this, together with the troubles created 
by the silt and grit which add friction to the bearings, 
overrules any otherwise excellent features that such 
meters might possess. 
Price’s criticism of the Ellis meter was also valid. 
Cross-sectional views of the heads of the two earliest 
versions of the Ellis meters are shown in figures 6 and 
7. It will be noted that in both of these figures the 
lower bearing is shown to consist of a pivot pointing 
downward into a cup-shaped receptacle that is in an 
ideal position to collect silt. Figure 7, illustrating a 
meter provided with a contact chamber, shows a 
further unsatisfactory condition. As the meters are 
lowered into water, the consequent increase in pres- 
sure causes the air within the chamber to compress, 
and silty water is forced upward through the bearing 
into the chamber. Once inside, the water becomes 
quiet, and the sediment settles out and lodges around 
48 BULLETIN 252: 
Figure 7.—CRross-sECTIONAL VIEW of later Ellis current 
(USNM cat. no. 289637.) 
meter. 
the upper end of the bearing. When the meter is 
raised out of the water, as is frequently the case during 
the course of a streamflow measurement, the water 
drains out of the contact chamber, but the sediment 
tends to cling to and remain on the bearing. Every 
time the meter moves vertically downward while in a 
river, more silt-bearing water enters the chamber, 
adding in turn an additional load of silt in the area 
from which it should be excluded. 
The drawing in figure 8 shows how Price managed 
to cause the open ends of both cup-shaped bearings to 
point downward. When this meter moves downward 

HUB AND BEARINGS 
ORIGINAL PRICE CURRENT METER 
(as constructed in 1882) 
Figure 8.—CRross-sECTIONAL VIEW OF HuB of the 
original Price current meter showing the arrange- 
ment by which the air was trapped in the bearing 
areas when the meter was submerged. 
CONTRIBUTIONS FROM THE MUSEUM OF HISTORY AND TECHNOLOGY 
