CONTENTS. 
PART I. (1876-1877.) 
I.—On the Application of Graphic Methods to the Determination 
of the Efficiency of Machinery. By Professor FLEEMING 
JENKIN, F.R.SS. L. & E. (Plates I.-XII.), 
II.— Additions to the paper “ On the Establishment of the Elemen- 
tary Principles of Quaternions, &c.,’ in the Transactions of 
the Royal Society of Edinburgh, Vol. XXVIII. By G. 
. Piarr, Docteur és-Sciences, ‘ ; ; 
III.—WNote on the Bifilar Magnetometer. By J. A. Broun, F.RS., 
IV.—On the Solutions of the Equation Vp¢p=0, op representing a 
LInnear Vector-Function, generally not Self-Conjugate. By 
GusTAV PiarR, Docteur és-Sciences. Communicated by 
Professor Tait, 
V.—Additional Memoir on the Parallel Roads of Lochaber.. By 
Davin Mitne Home, LL.D. (Plates XIII., XIV.), 
VI—Least Roots of Equations. By J. Doucias Hamitton Dickson, 
B.A., F.R.S.E., Fellow and Tutor of St Peter’s College, 
Cambridge, 
VII.—On FKisenstein’s Continued Fractions. By THomas Mutr, 
M.A, 
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