During the natural draught trial the vessel obtained a mean speed of 18.68 knots, on an average of 943/4 revolutions—­the forced draught having been done on an average of 1051/2 revolutions.  The consumption trial, which lasted twelve hours, was made to determine the radius of action, when the ship showed that at a speed of 11.6 knots she could steam a distance of 5,900 knots.  Further trials took place to test the evolutionary powers of the vessel, though these trials were not specified in the contract.

The vessel, as may be seen from the engravings, is fitted with a rudder of a new type, known as Thomson & Biles’ rudder, with which it is claimed that all the advantage of a balanced rudder is obtained, while the ship loses the length due to the adoption of such a rudder.  It is formed in the shape of the hull of the vessel, and as the partial balance of the lower foreside gradually reduces the strains, the rudder head may be made of very great service.  As a matter of fact, this rudder is 230 ft. in area, and is probably the largest rudder fitted to a warship.  The efficiency of it was shown in the turning trials, by its being able to bring the vessel round, when going at about nineteen knots, in half a circle in one minute twenty-three seconds, and a complete circle in two minutes fifty-eight seconds, the diameter of the circle being 350 yards.  This result, we believe, is unrivaled, and makes this vessel equal in turning capabilities to many recent warships not much more than half her length.

* * * * *

FILM NEGATIVES.[1]

  [Footnote 1:  A communication to the Birmingham Photographic
  Society.]

Having had a certain measure of success with Eastman stripping films, I have been requested by your council to give a paper this evening dealing with the subject, and particularly with the method of working which my experience has found most successful.  In according to their request, I feel I have imposed upon myself a somewhat difficult task.

There is, undoubtedly, a strong prejudice in the minds of most photographers, both amateur and professional, against a negative in which paper is used as a permanent support, on account of the inseparable “grain” and lack of brilliancy in the resulting prints; and the idea of the paper being used only as a temporary support does not seem to convey to their mind a correct impression of the true position of the matter.

It may be as well before entering into the technical details of the manipulation to consider briefly the advantages to be derived—­which will be better appreciated after an actual trial.

My experience (which is at present limited) is that they are far superior to glass for all purposes except portraiture of the human form or instantaneous pictures where extreme rapidity is necessary, but for all ordinary cases of rapid exposure they are sufficiently quick.  The first advantage, which I soon discovered, is their entire freedom from halation.  This, with glass plates, is inseparable, and even when much labor has been bestowed on backing them, the halation is painfully apparent.