Amphibia (the amphibians) is a class of vertebrate animals, which in their early life breathe by gills or branchiae, and afterwards partly or entirely by lungs. The Frog, breathing in its tadpole state by gills and afterwards throwing off these organs and breathing entirely by lungs in its adult state, is an example of the latter phase of amphibian existence. The Proteus of the underground caves of Central Europe exemplifies forms in which the gills of early life are retained throughout life, and in which lungs are developed in addition to the gills. A second character of this group consists in the presence of two occipital condyles, or processes by means of which the skull articulates with the spine or vertebral column; Reptiles possessing one condyle only. The class is divided into four orders: the Ophiomorpha (or serpentiform), represented by the Blind-worms, in which limbs are wanting and the body is snake-like ; the Urodela or Tailed Amphibians, including the Newts, Proteus, Siren, etc; theAnoura, or Tailless Amphibia, represented by the Frogs and Toads; and the Labyrinthodontia, which includes the extinct forms known as Labyrinthodons. Research Amphibia
In modern warfare, the term cannon is applied to a shell-firing gun of a heavier calibre than a machine gun. They have a lower rate of fire, but are more destructive than machine guns. Before the Great War, all big guns which we would now refer to as howitzers and anti-tank guns etc were called cannons, irrespective of whether they were muzzle or breech loaded.
In older warfare, the term cannon was applied to a big gun or piece of ordnance. The precise period at which engines for projecting missiles by mechanical force (catapults, etc) were supplanted by those utilizing explosive materials is a matter of controversy, the invention of cannon being attributed to the Chinese, from whom the Saracens may have acquired the knowledge. A doubtful authority asserts their use at the siege of Belgrade in 1073; but they were certainly brought into use in France as early as 1338. At first they were made of wood, well secured by iron hoops, the earliest shape being somewhat conical, with wide muzzles, and afterwards cylindrical. They were then made of iron bars firmly bound together with iron hoops like casks, Mons Meg at Edinburgh being a good example.
The first cannons used in Britain appeared around 1335. Edward III used cannons at the Battle of Cressy. In the reign of Elizabeth I, the British cannon was a muzzle-loading gun with an 8-inch bore that fired a 60 lb projectile. Bronze was used in the second half of the 14th century, towards the close of which and during the 15th century cast-iron ordnance came into use. A form of breech-loading cannon was introduced in the 16th century.
Cannon formerly received the following distinctive names: cannon royal, or carthoun, carrying 48 pounds; culverin, 18; demi-culverin, 9; falcon, 6; basilisk, 48; siren, 60; etc. They were afterwards named from the weight of the balls which they carried: 6-pounders, 12-pounders, etc; but by 1900 were often, especially the large ones, designated by their weight, as a 25-ton gun, a 67-ton gun, an 80-ton gun, etc. Their calibre or diameter of bore was also used in designating them: a 6-inch gun, a 12-inch gun, etc.
Around the 19th century the classification of cannons into muzzle-loading and breech-loading came into use though all the guns of the improved types of the 19th century were breech-loading. Quick-firing guns and machine-guns were classes of introduced late in the 19th century.
Great improvements and changes in the manufacture of cannon were introduced in the late 19th century. Not long before they were all made of iron, brass, or gun-metal (a variety of bronze) by casting. The introduction of rifled small-arms led the way to that of rifled cannon, and the adoption of heavy armour for ships of war rendered guns of enormous power and magnitude necessary in order to penetrate their sides. For round balls projectiles of considerable length were substituted in the rifled ordnance; and the increased weight and inertia of the projectiles and their rapid rotation in these rifled guns try the piece so severely that cast-iron and bronze were superseded, and the old methods of making guns given up. Guns built up in different ways are now in general use, and the construction and connected mechanism is now somewhat complicated, so that to turn out a large gun of modern type is a long and expensive process. In Englandsteel and wrought-iron guns came in for all heavy artillery by 1900, and they were manufactured for foreign powers on a large scale, especially by the Elswick Ordnance Company.
The former heavy guns of the British service, made on the 'Woolwich' system, had a steel tube to form the bore, over which were shrunk coils of wrought-iron, increasing in thickness about the breech, This method of manufacture was first introduced by Sir William Armstrong about 1858. Such guns present the hard steel to meet the wear and tear on the bore of the gun, while great support is given by shrinking on the wrought-iron hoops, which contract with a tight grip upon the steel. Hoops of steel were later preferred to those of wrought-iron; and later still the guns were strengthened by flat steel wire or a narrow ribbon of steel coiled round it.
Steel guns of very high quality were long made by Krupp of Essen, and Sir J. Whitworth's guns also gained a high name. The Whitworth guns were made of mild steel of a special quality, massive hoops being forced over a central tube, and over one another, by shrinkage or by hydraulic pressure. These guns had comparatively small hexagonal bores, with a very rapid twist, and fire long projectiles, made to fit mechanically, with remarkable accuracy to a great range.
The Siren C.30S Edelweiss was a French single-seat Standard Class sailplane first flown in 1962, and finishing second in the Standard Class at the 1963 World Gliding Championships. The Siren C.30S Edelweiss was a shoulder-wing cantilever monoplane of mixed construction and a top speed of 225 kmh in smooth air. Research Siren C.30S Edelweiss
A jumpsuit, originally called a 'siren suit', is a baggy complete body covering with a zip front fastening designed so as to be put on and taken off quickly. Research Jumpsuit
Abbreviations
Research Amphibia
