To regulate the heat it is necessary either to instal a number of small radiators or to divide the radiators into sections, each section controlled by distinct valves; steam may then be admitted to all the sections of the radiator or to any less number of sections as desired.
The perforation of the paper when done by hand is usually performed by means of small mallets, but at the central telegraph office in London, and at other large offices, the keys are only used for opening air-valves, the actual punching being done by pneumatic pressure.
- Bb Cornet with enharmonic valves (Besson & Co.).
It receives the three great venous trunks of the body, namely the vena cava superior dextra, the vena cava superior sinistra more dorsally, and the vena cava inferior more to the right and below; the opening of the last is guarded by two prominent valves in place of the mammalian valvula Eustachii.
The blood leaves the heart past three semi-lunar valves, by the right aorta, this being alone functional, a feature characteristic of, and peculiar to, birds.
All types of valves are with few exceptions operated by a link motion, generally of the Stephenson type, occasionally of the Allan type or the Gooch type, or with some form of radial gear as the Joy gear or the Walschaert gear, though the latter gear has characteristics which ally it with the link motions.
Illustrations of these gears are given in the article Steam Engine, and the complete distribution of steam for both forward and backward running is worked out for a typical example of each of them in Valves and Valve Gear Z1 ecl.cnisms by W.
Generally steam from the boiler is admitted direct to the low-pressure cylinder through a reducing valve, and valves and devices are used to prevent the steam so admitted acting as a back pressure on the high-pressure cylinder.
A, ventral, B, dorsal valves; 1, loop; q, crura; ss, septum; c, cardinal process.
Valves to move forward h, Central muscles (close valves).
(b) Bairdiidae, which have the valves smooth, with the hinge untoothed.
Considering the imprisonment of the ostracod body within the valves, it is more surprising that the Asteropidae and Cypridinidae should have a pair of compound and sometimes large eyes, in addition to the e median organ at the base of I the " frontal tentacle," than 6 that other members of the group should be limited to P that median organ of sight, or have no eyes at all.
As might be expected, in thickened and highly embossed valves thin spaces occur over the visual organ.
The young, though born with valves, have at first a nauplian body, and pass through various stages to maturity.
The two valves of the shell of the common cockle are similar to each other, and somewhat circular in outline.
The discharge at the weir whilst it is raised is effected either by partially tipping some of the shutters by chains from a foot-bridge, or by opening butterfly valves resembling small shutters in the upper panels of the shutters.
He loves to climb the bed-posts and unscrew the steam valves much better than to spell, but that is because he does not understand that words would help him to make new and interesting discoveries.
Whenever I see the movement of a locomotive I hear the whistle and see the valves opening and wheels turning; but I have no right to conclude that the whistling and the turning of wheels are the cause of the movement of the engine.
I see only a coincidence of occurrences such as happens with all the phenomena of life, and I see that however much and however carefully I observe the hands of the watch, and the valves and wheels of the engine, and the oak, I shall not discover the cause of the bells ringing, the engine moving, or of the winds of spring.