service in Mesopotamia, the main details being: Length, 230 ft.; beam, 36 ft.; displacement circa 1000 tons; armament, two 6-inch and smaller Q. F. Twelve smaller gunboats, known as the Fly class, were also built in England, shipped in sections to Abadan, Mesopotamia, and there assembled and armed for service on the Tigris and Euphrates. Dimensions: Length, 120 ft.; beam, 19.7 ft.; draft, 2.6 ft.; armed with one 4-inch., also 6-pounder Q. F. and machine guns.

Of the 200 or more destroyers which have been completed since the outbreak of war full particulars are not yet available, but they are understood to be similar in many respects to the L and M classes completed between 1913-1915. Displacements range from 965 to 1000 tons, speed nominal, from 30 to 35 knots, and the armament comprises three or four 4-inch Q. F., one 3-inch anti-aircraft gun, and four 21-inch torpedo tubes. In all the later boats broadside fire has been increased by adopting the center-line position for all guns.

A larger class of destroyers, known as flotilla leaders, completed during the war, comprised at least 13 boats. They are understood to displace about 1200 tons, with a designed speed of 32 knots, and to be armed with four 4-inch Q. F., one 3-inch A.-A. gun, and four torpedo tubes.

We would emphasize the fact that the vessels enumerated in the foregoing do not by any means include all the new construction undertaken for the British Navy since the outbreak of war, and that the particulars may need correction, but the information given is sufficient to convey some idea of the huge scale of naval construction in this country, during the past four years. The Engineer, 29/11.

Note: No information regarding battle cruisers, submarines or monitors, etc.

Destroyers, as is well known, have played a leading part in the defeat of Germany at sea. Not merely did they get home again and again on the German Fleet as it fled from the Jutland battle, but the destroyers have been the terror of the U-boat. For obvious reasons it has not been possible to publish until now any details of the more recent of our additions to these craft, but the declaration of the armistice has relaxed the restrictions in vogue, and we are thus enabled to give an illustration and some particulars of the destroyer Mounsey, the boat which, under the command of Lieutenant Craven, saved, under circumstances of very great difficulty, no less than 696 lives when the Otranto was torpedoed on October 6 last. The sea at the time was exceedingly rough, and it would have been fatal to have brought a lightly constructed vessel like the Mounsey alongside of the cruiser. The saving of life was therefore effected by maintaining the Mounsey under way, so that she passed the Otranto within a few feet, allowing the people to jump from one ship to the other. The maneuver had to be repeated many times, and was, under the circumstances, a very original and successful method of rescuing those endangered without great risk to the destroyer herself.

The Mounsey was built by Messrs. A. F. Yarrow and Co., Ltd., at their Scotstoun works, and on her measured mile trials attained a speed of over 39 knots. This trial was run with the boat fully armed and equipped, and with sufficient fuel on board for a run of 1000 miles at an economical speed. Further particulars are given below:

Three 4-inch quick firers; two 2-pounders; two twin 21-inch

torpedo tubes.

Complement-79.

BRITISH SUBMARINES DESTROY MANY ENEMY CRAFT.-Details can now be given of the part which British submarines played during the war. This service destroyed the following enemy warships:

Two battleships, two armored cruisers, two light cruisers, seven destroyers, five gunboats, twenty submarines and five armed auxiliary vessels. Three battleships and one light cruiser were torpedoed but reached port badly damaged.

Other enemy craft destroyed were:

One Zeppelin, fourteen transports, two ammunition and supply ships, two more ships, fifty-three steamships and 197 sailing ships.

In no case was a merchant ship sunk at sight. Care was taken to see the crews of all vessels got away safely.

In addition to carrying out their attacks on enemy war craft, the submarine commanders carried out 24 cruises, totaling 22,000 miles, which probably constitutes a record for any submarine.-Naval Monthly, 18/12.

NORTH SEA BLOCKADE.-The First Lord of the Admiralty (Sir Eric Geddes), speaking at the "Sea Power Exhibition" on December 4, said it was the blockade which crushed the life out of the Central Empires. Largely that blockade was carried out by the Tenth Cruiser Squadron with its flagship the Alsatian, which from 1914 to 1917 held the 800 miles of grey seas from the Orkneys to Icelands, and which had intercepted 15,000 ships conveying succor to the enemy. That service had been performed in Arctic conditions of storm, blizzard, and ice, and yet, in spite of almost impossible conditions, only four per cent of the vessels were missed.-Army and Navy Gazette, 14/12.

BRITISH SHIPS SUNK DURING THE WAR.-Sir Eric Geddes states that during the war 2475 British ships were sunk with their crews beneath them, and 3147 vessels were sunk and their crews left adrift. The personnel of the merchant marine service was heavily hit, the total number of casualties exceeding 15,000 men. The U-boats carried on continuous warfare against the fishing fleets; the total number of fishing vessels sunk being 670.Scientific American, 21/12.

CANADA'S SHIPBUILDING IN WAR PERIOD.-Some 360 ships were constructed in Canada for Canadian registry during the period of the war to the end of November. Of the number, 199 were sailing vessels, aggregating 44,135 gross tons, and 160 were steamships, totalling 69,612 tons. In addition, 22 ships were built through the Imperial Munitions Board for the British Government. Of the number, there were 15 each of 1400 net tons and 7 each of 2600 net tons.

Contracts for 42 steel steam vessels, with an aggregate capacity of 255.250 tons, have been placed under the Dominion Government's shipbuilding program; of these, two have been launched at Montreal.

The total capacity of Canadian shipyards is 460,000 tons a year.—Nautical Gazette, 14/1.

LOSSES FROM COLLISIONS DURING THE WAR.-It is hoped, says London Fairplay, that the serious losses from collision which have been such a feature for the last two years will be sensibly lessened with the cessation of the convoy system. There is still, however, the difficulty due to the dazzle system of painting vessels, for, although this system handicapped a submarine commander in judging the position and direction of a vessel, it would handicap the master of an approaching vessel in a similar fashion. The number of vessels sunk by collision in November was eight, and the total number sunk for the eleven months this year is 90. The totals for the three previous years are as follows:

1915
1916

1917

.25 vessels.

.33 vessels.

.66 vessels.'

It will be seen, therefore, that under ordinary conditions the total losses for 1918 are likely to reach a figure which is 50 per cent more than in 1917 and 300 per cent more than in 1916.

THE ROYAL AIR FORCE. For the first time during the war, it is possible to disclose official details of the remarkable fighting aircraft which enabled the Royal Air Force to play so notable and conclusive a part in the aerial defeat of Germany and her Allies. It is well known that during the final stages of the war Great Britain has been turning out large numbers of the fastest and most powerfully armed aircraft in the world. Indeed, the collapse of Germany in the air, which was so noticeable a feature of the last phase of the operations, was largely due to the fact that, not only was she confronted with an air force immensely superior to her own in all those personal qualities which constitute fighting morale, but that she was at last definitely outclassed in the speed, climb and fighting efficiency of the super-aircraft which British inventive genius brought into the field. Roughly, the machines employed by the Royal Air Force upon the fighting fronts may be divided into three groups: (1) Reconnaissance Machines: Used for contact patrol work over the lines, the direction of artillery fire, photography, and general strategical reconnaissance. (2) Heavy Bombers: Capable of travelling long distances without escort, and carrying heavy loads of bombs in addition to defensive armaments. (3) Fast Fighting Scouts: Possessing exceptional climbing powers, heavily armed, and capable of maneuvering at a very high rate of speed.

The earliest type of British reconnaissance machine was the now famous B. E.-2 C, designed and produced by the Royal Aircraft Factory at Farnborough. The design was completed just prior to the outbreak of war, a fact which facilitated immediate production for the use of the Expeditionary Force. As far as possible, speed, climb and maneuvering ability were combined, although compared with modern types it was a relatively slow machine, making only 50 miles to 60 miles an hour with the 80 h. p. engine with which it was originally fitted. This was followed by the Armstrong-Whitworth F K.-8, fitted with 160 h. p. Beardmore engines which made an average speed of 82 miles an hour and could climb to 10,000 feet in about 27 minutes. Towards the end of 1916, an immense forward stride was taken by the production at the Royal Aircraft Factory of the R. E.-8 with a 12 cylinder R. A. F. engine. This machine has done the bulk of the artillery observation work in France, directing all big-gun fire and barrage work. At 10,000 feet it has a speed of 92 miles an hour, and can climb to that height in 11 minutes. It is fitted with camera and wireless equipment, and takes photographs of every "shoot." An even bigger advance was marked by the introduction of the Bristol Fighter, a long distance fighting reconnaissance machine, capable of travelling at 113 miles an hour at 10,000 feet, and climbing to that height in II minutes. Had the war continued, the Bristol Fighter would have entirely replaced the R. E.-8 for long distance artillery work.

Aerial bombing was first undertaken in France by the Avro, a machine of moderate speed fitted with an 80 h. p. Gnome engine. The observer's seat was used as a receptacle for the bombs, which were merely thrown overboard without the aid of the scientific bombing sights and elaborate bomb-dropping gear which have since contributed so largely to the wonderfully accurate shooting made during the raids upon Germany. The first British machine specially constructed for bombing purposes was the Short, a modified seaplane, fitted with a 250 h. p. engine, and carrying four 112-lb. bombs under each wing. This type, which did most useful work in France, was followed by the Sopwith 12 Strutter, and later by the highly-improved D. H.-4 and D. H.-9 machines. The D. H.-4 machine was originally designed as a fighter, but its trials disclosed such excellent lifting powers that it was converted to bombing purposes. It is capable of climbing to 10,000 feet in nine minutes, and has an endurance of three and three-fourths hours. The D. H.-4 and D. H.-8 machines have been fitted with RollsRoyce, B. H. P., and latterly the Liberty engines.

Finally, the great Handley-Page machines were devised for the bombing of Germany. The first quantity production was begun in August, 1917, and the performance of the machine has justified the highest expectations. It is capable of carrying 2000 lb. weight of bombs in the fuselage, or 1500 lb. to suspend externally. The machines used by the Royal Aircraft Independent Force, in the bombing of Germany have been the HandleyPage, D. H.-4, D. H.-9, and Sopwith Camel. Not until the middle of 1915 were production machines armed with standard equipment. Two of the earliest types were the F. E.-2 B. and the Vickers' Fighter. Both had an open cockpit, and were equipped with Lewis or Vickers' machine guns. The year 1916 witnessed the introduction of the fixed machine gun firing through the propeller and fitted with the ingenious Constantinesco interrupter gear. Other types followed, rapidly leading up to the S. E.-5 a, and lastly the Sopwith Dolphin, the best and latest British fighting scout in the field. Both these types were in use at the termination of hostilities. Some idea of the power of these modern aircraft can be gained from the fact that the Dolphin travels at 128 miles an hour at 10,000 feet, and climbs to that height in 84 minutes. It lands at upwards of 55 miles an hour. The following table shows the performance of the leading British types. (At lower altitudes the machines will, of course, develop higher speeds):

BRITISH AIRSHIPS.-In 1909, the Admiralty decided to experiment with rigid airships, the outcome of this decision being Naval Airship No. 1, which showed by its failure to rise that it was not a simple matter to construct these vessels, and when lightened by alteration of construction, it broke in two in 1911. It was given out the following year that the prospects of using this type of airship were not sufficient to justify the great cost. The nation that was to be our main enemy in the greatest war of all time thought otherwise, and backed their opinion, continuing to construct and improve on the Zeppelin model, with the result that on many occasions, and notably in their dire need at the battle of Jutland Bank, they reaped the reward of their consistent policy of enterprise and at relatively infinitesimal cost. At the outbreak of hostilities Great Britain had only seven airships, all of the non-rigid type, four of which had been taken over by the Admiralty on December 31, 1913, and of the remaining three, No. 2 was the model on which all the S. S. (submarine scout) class of vessel have since been based; No. 3 was an Astra-Torres of trefoil section with internal rigging, and No. 4 was a Parseval bought from Germany. It was the irony of fate that this particular vessel should have been used to patrol the Channel on the night of August 5 and 6, 1914, following up the declaration of war with that country.

Since then, four types of non-rigid airships have been constructed for naval account in Great Britain-Parseval, Submarine Scout, Coastal, and North Sea. The second of these is rigged externally to Eta patches on the envelopes, these patches deriving their name from one of the four army airships alluded to above, on which they were first used. The two lastnamed are constructed on the Astra system. The year 1915 saw the first building of small S. S. airships, and they repaid their cost many times over; the original model consisted of an aeroplane body with super-imposed more or less stream-lined envelope; this was followed by S ̊ S. Zero, a vessel of 70,000 cubic feet capacity, with a blunt-nosed envelope 145 feet in length, and a main diameter of 29 feet. The longest flight of one of these vessels was just under 51 hours. In 1917 the S. S. Twin made its appearance, its length is 1642 feet, main diameter about 32 feet, cubic capacity 100,000 feet, the car carries a crew of three, and this class of airship has been found so eminently satisfactory that no more of the previous S. S. models will be built. The motive power is supplied by twin engines, two 75 h. p. Hawks. The Coastal type has a capacity of 200,000 cubic feet, and the car will hold five men. Airships of this type did most of the long distance patrols during the last two years, and were largely employed in convoying ships from beyond the Scilly Isles up the Channel. An improved