494 
: NATURE 
4 
% > , 
ciSal 
c 3 \ en vag 
[March 23, 1882 
. 
Decl.+81° 105. The star is No. 113-4 of Fedorenko’s 
Catalogue. : 
The following are times of minima of U Cephei to the end 
of SE ge inferred by Mr. Knott from his observations on 
M: 18 :— 
h. m. h. m. 
March 23... 12 0 G.M.T, | April 12 ... 10 37 G.M.T. 
2S nck 30” ss 17). IO TON! 55 
2 tk IS oS5; 22 ae aS eas, 
April 
7.1058 ,, 27. 934 4, 
THE CURRENT METER OF PROF. A. R. 
HARLACHER* 
PROF. HARLACHER, of the Technical High School at 
Prague, was the first to construct a current meter which 
obviates all the difficulties and drawbacks of the instruments 
Fre. 1. 
previously employed. The Harlacher current meter permits the 
velocity to be determined in the shortest possible time. 
It is unnecessary to describe all the stages in the invention of 
the present form of the Harlacher meter. It is sufficient to say 
* By Richard Blum, City Engineer, Leipzig. From advanced copy of a 
Paper in the Proceedings of the Institution of Civil Engineers, by permission 
of the Council. 
that Prof. Harlacher worked for several years at its improve- 
ment, and that his success was acknowledged by the award, at 
the Paris Exhibition, of two gold medals. ; 
The Harlacher meter is constructed as follows :—For the — 
movable staff, on which the Woltmann meter is fixed, an im- — 
movable staff or rod is substituted, which is planted firmly in 
the bed of the river, and along which the meter slides up and 
down during the observations on any one vertical. This rod is’ 
a cast-iron tube, with a solid point at the lower end, A, A (Fig. _ 
Fic. 2. 7 
1). The other parts of the apparatus, except the electric bat- 
tery and indicator, are fastened to the tube, so that the whole 
can be moved from one vertical to another, without having to 
be taken apart. The screw of the meter, B, is two-bladed. For 
very small velocities, it would be preferable to adopt a four- 
bladed screw of larger diameter. The screw is fixed on a steel 
shaft, 4 (Fig. 2), which has an eccentric enlargement at one’ 
point, 4,. This makes contact with the steel spring, 44, at each 
revolution of the meter. These contacts complete the electric 
circuit, and the current which passes actuates the electric clock 
The weight of the screw B, the shaft 4, and the 
or indicator, 
brass box 6, which carries the shaft, is balanced by a counter- 
weight 4, (Figs. 1, 2, and 3). This keeps the axis of the instru- 
ment in a perfectly horizontal position. ‘The screw, 4, serves 
to regulate the pressure of the spring, 4,, while the two screws, 
4,, fasten the spring to the brass frame which surrounds and 
protects the shaft. ‘he sbaft is square at the end, which receives 
the screw, which is put on and held fast by a nut, 4, (Figs. 2 and 
3). The brass frame, 4g, is fixed to a hollow cylinder, Cc. Below 
the hollow cylinder, ¢, is a plate, c, (Figs. 2 and 3), which pre- 
