THE EOYAL AETILLEEY INSTITUTION 
151 
DESCRIPTION 
OP 
NAYEZ’S. ELECTRO-BALLISTIC APPARATUS,* 
FOE DETEEMINING- THE VELOCITY OF PEOJECTILES. 
By Lieutenant W. H. NOBLE, R.A. 
Haying been requested by the R.A. Institution to furnish them with a 
full description of this apparatus, as a supplement to the valuable report by 
Captain Noble, late R.A., printed in the R.A. Institution “ Proceedings,” 
Vol. III. p. 117, I beg to submit the following pages in hopes that they 
may prove acceptable. Captain Noble has given a short account of this 
instrument which, although quite sufficient for a report to those who were 
intimately acquainted with the apparatus, was not intended for the guidance 
of such as have never had an opportunity of witnessing experiments with 
the electro-ballistic machine. 
In order thoroughly to understand the nature and working of the instru¬ 
ment, the reader must be somewhat acquainted with the elements of 
electricity, galvanism, and magnetism, which can be studied in any book on 
the subject. 
I would suggest attention to the following points :— 
(1) Nature of an electric current. 
(2) Conductors and non-conductors of electricity. 
(3) The voltaic battery. Elements of Bunsen’s, and Groves’s batteries. 
(4) Magnetization of soft iron by the electric current. Electro magnets. 
(5) The necessity of complete insulation in the wires conducting electric 
currents. 
(6) Velocity of the propagation of electricity. 
1. Major Navez's electro-ballistic apparatus consists of three distinct 
and separate parts :— 
The Pendulum Proper. 
The Conjunctor. 
The Disjunctor. 
* Major Navez, Belgian Artillery, Las published a book of instructions on this subject, which 
has been very clearly translated by Lieut.-Col. C. W. Younghusband, E.A. 
The diagrams and woodcuts belonging to this translation have been placed at the disposal of the 
E.A. Institution by the War Office. 
[VOL. III.J 
D 
