1919.] 
Departmental Reports. 
127 
tabulation of values if the flow is variable, which values can afterwards 
be plotted to any scale, or the charts may be used as a basis for a 
graphical process by which the various elements which go to make up 
the complete curve of rise and fall may be pieced together as described 
herein. 
A graphic process of obtaining the rate of storage from a given 
inflow is described in the Engineering Neivs Record of the 2nd August, 
1917,* and since this paper was written another and more complete 
treatment of the whole subject with references to previous papers 
appeared in the same publication for the 5th September, 1918.1 The 
treatment is, however, different from that adopted in this paper, and, so 
far as I know, no charts of the functions of ( ] have been published. 
\H 1 
The charts for a rising lake-level may be easily constructed by the aid of 
Gould’s functions, already referred to ; but no tables of values are avail¬ 
able, so far as I know, which will enable the falling lake-level to be 
calculated. 
The charts were drawn by Mr. A. J. Hainsworth, of this office, from 
calculations by Mr. A. C. Owen, and are used in the Electric-power 
Branch of the Public Works Department in the manner herein described, 
and have been found most useful in enabling the graphs of rising and 
falling reservoir-level to be obtained in an expeditious and satisfactory 
manner; and it was only after a study and trial of various other methods 
that the system described herein was evolved. The main object of the 
present paper is to preserve a record of the origin and principles upon 
which the charts are constructed, and to standardize the method of using 
the same. 
The Electrical Properties of Three-phase Transmission¬ 
lines. 
By E. Parry, B.Sc., M.I.E.E., A.M.I.C.E., Chief Electrical Engineer, 
Public Works Department. 
Introduction. 
This paper is prepared primarily for the use of departmental officers in 
designing transmission-lines, with the object of economizing time and 
of standardizing the method of calculation. The principal obstacle in the 
way of rapid evaluations of problems connected with high-tension trans¬ 
mission at the present time is the lack of suitable tables. In particular, 
tables are lacking of the hyperbolic functions of complex quantities. 
Miller’s]; tables are the most extensive available, but entail a good deal 
of interpolation of values throughout the range covered by transmission¬ 
line problems. Kennedy has published tables from time to time, the 
most useful ones for present purposes being those in a paper contributed 
* Harold A. Thomas, Flood-retarding Reservoir Problem directly solved, En<j. 
News Record , vol. 79, p. 226. 
f Robert E. Horton, Determining the Regulating Effect of a Storage Reservoir, 
Eng. News Record , vol. 81, p. 455. 
I W. E. Miller, Formulae, Constants, and Hyperbolic Functions for Trans¬ 
mission-line Problems, General Electric Review Supplement, May, 1910. 
