e instance of Mr. Mackie, who had previously gone very
thoroughly into the subject, a Committee of the Elder Brethren visited
the cotton-powder manufactory, on the banks of the Swale, near
Faversham, on the 16th of June, 1877. The weights of cotton-powder
employed were 2 oz, 8 oz, 1 lb, and 2 lbs, in the form of rockets and
of signals fired a few feet above the ground. The experiments
throughout were arranged and conducted by Mr. Mackie. Our desire on
this occasion was to get 'as near to windward as possible, but the
Swale and other obstacles limited our distance to 1.5 mile. We stood
here E.S.E. from the firing-point while the wind blew fresh from the
N.E.

The cotton-powder yielded a very effective report. The rockets in
general had a slight advantage over the same quantities of material
fired near the ground. The loudness of the sound was by no means
proportional to the quantity of the material exploded, 8 oz. yielding
very nearly as loud a report as 1 lb. The 'aerial echoes,' which
invariably followed the explosion of the rockets, were loud and
long-continued.

On the 17th of October, 1877, another series of experiments with
howitzers and rockets was carried out at Shoeburyness. The charge of
the howitzer was 3 lbs. of L. G. powder. The charges of the rockets
were 12 oz, 8 oz, 4 oz, and 2 oz. of gun-cotton respectively. The gun
and the four rockets constituted a series, and eight series were fired
during the afternoon of the 17th. The observations were made from the
'Vestal' and the 'Galatea,' positions being successively assumed which
permitted the sound to reach the observers with the Wind, against the
wind, and across the wind. The distance of the 'Galatea' varied from
3 to 7 miles, that of the 'Vestal,' which was more restricted in her
movements, being 2 to 3 miles. Briefly summed up, the result is that
the howitzer, firing a 3-lb. charge, which it will be remembered was
our best gun at 'the South Foreland, was beaten by the 12-oz. rocket,
by the 8-oz. rocket, and by the 4-oz. rocket. The 2-oz. rocket alone
fell behind the howitzer.

It is worth while recording the distances at which some of the sounds
were heard on the day now referred to:

1. Leigh 6.5 miles W.N.W. 24 out of 40 sounds heard.

2. Girdler 12 miles S.E. by E. 5 out of 40 sounds heard.
Light-vessel

3. Reculvers 171 miles S.E. by S. 18 out of 40 sounds heard.

4. St. Nicholas 20 miles S.E.