The improvements in gun mountings mentioned above led the way to the introduction of the automatic sight.
It was found impossible to make the Morse ink writer so sensitive that it could record signals sent over land lines of several hundred miles in length, if the speed of transmission was very much faster than that which could be effected by hand, and this led to the adoption of automatic methods of transmission.
Automatic couplers resembling the Janney are adopted in a few special cases in Great Britain and other European countries, FIG.
The Murray automatic system was designed specially for dealing with heavy traffic on long lines.
In certain respects, on the other hand, America has gone further than the United Kingdom, especially in the matter of automatic signalling, and in the operating of points and signals by electrical power or air-pressure instead of manual labour.
In America, also, freight trains are fitted with an automatic continuous brake, whereas in the United Kingdom this appliance is required by law only in the case of passenger trains, and in fact is not fitted to goods and mineral trains except in a few isolated instances.
This body pursued the subject with more or less diligence, and in 1884 laid down the principle that the automatic coupler should be one acting in a vertical plane - that is, the engaging faces should be free to move up and down within a considerable range, in order to provide for the differences in the height of cars.
The Chaff-cutting Machines (Accidents) Act 1897 is a measure very similar in its intention to the Threshing Machines Act 1878, and provides for the automatic prevention of accidents to persons in charge of chaff-cutting machines.
Cigarettes were entirely prepared by the smoker himself; Ci but now they are very largely made by automatic machinery.
But it is still more curious that it was not afterwards carried out, for the communication of automatic symmetrical motion to both segments only involves a simple alteration previously described.
By a modification of this apparatus the message, instead of being immediately re-transmitted into the second cable, can be punched on a paper slip, which can be inserted in the usual way into an automatic transmitter, so as to send either cable or Morse signals.
The use of automatic couplers for freight cars throughout the United States, introduced in 1893-1900, greatly reduced the number of deaths and injuries in coupling, and the use of air brakes on freight cars, now universal, has reduced the risk to the men by making it less necessary for them to ride on the roofs of high box-cars, while at the same time it has made it possible to run long trains with fewer men; but except in these two features the freight service in America continues to be a dangerous occupation.
The common form of non-automatic coupler, used in Great Britain for goods wagons, consists of a chain and hook; the chain hangs loosely from a slot in the draw-bar, which terminates in a hook, and coupling is effected by slipping the =chain of one vehicle over the hook of the next.
The investigation of Carpenter on unconscious cerebration and of Faraday on unconscious muscular action showed early in the movement that it was not necessary to look outside the medium's own personality for the explanation of even intelligent communications unconsciously conveyed through table-tilting, automatic writing and trance-speaking - provided the matter communicated was not beyond the range of the medium's own knowledge or powers.
When cordite replaced black powder, and the gun sights and all in front of the gun were no longer obscured by hanging clouds of smoke, it became a desideratum, and, as the automatic sight, it was reintroduced by Sir G.
The first method is in general use for steam cranes; it allows for a far greater range of power in the brake, but is not automatic, as is the second.
Normally a switch attached to the key cuts the battery off, and connects the line direct through the receiving relay; this switch is turned to " send " when transmission commences, and is moved back to " receive " when it ceases: this movement is done quite mechanically by the telegraphist, and as it is practically never forgotten, automatic devices (which have often been suggested) to effect the turning are wholly unnecessary.
The messages in the form of perforated tape are then passed through an automatic transmitter, something like a Wheatstone transmitter, at a speed of about 100 words a minute.
The Murray automatic system is not regarded as suitable for short telegraph lines or moderate traffic, printing telegraphs on the multiplex principle being considered preferable in such circumstances.
The heavier cores, with the consequent advance in speed of working attainable, have necessitated the introduction of automatic sending, the instruments adopted being in general a modification of the Wheatstone transmitter adapted to the form of cable signals, while the regularity of transmission thus secured has caused its introduction even on circuits where the speed cannot exceed that of the ordinary operator's hand signalling.
The automatic curb sender was originally designed by Lord Kelvin for the purpose of diminishing the effect of inductive re- Au tardation in long cables.
By the automatic curb sender the cable is put to one or the other pole of the battery and then to the reverse pole for definite proportionate times during u b c 0 'c' C p t e a n i m e r rn e ll i a.
Owing to the difficulty of maintaining perfect balance on duplexed cables, curb sending is not now used, but the signals are transmitted by means of an apparatus similar to the Wheatstone automatic transmitter used on land lines and differing from the latter only in regard to the alphabet employed; the signals from the transmitter actuate a relay having heavy armatures which in turn transmit the signals to the cable; this arrangement gives very firm signals, a point of great importance for good working.
At the receiving end are a similar antenna and resonant circuit, and a telephone is connected across one part of the latter through an automatic interrupting device called by Poulsen a " ticker."
A long-standing cause of complaint on the part of the public has been the common refusal of cab-drivers to accept their legal fares, but, on the other hand, several attempts to introduce cabs with an automatic taximeter failed, until the introduction of motor cabs, of which a few had already been plying for some time when in 1907 a large number, provided with taximeters, were put into service.
Thus the simple connexion of the two screws by cogwheels to give them automatic opposite motion is not an available method unless the separation of the segments is independently measured by scales.
21 and 22, which show a combined rocking-bar and automatic sight.
In the Wheatstone automatic apparatus three levers are placed side by side, each acting on a set of small punches and on mechanism for feeding the paper forward a step after each operation of the levers.
This received perforated tape is then used to control what is known as the printer or automatic typewriter, a machine that translates the tape perforations into letters and prints the messages in Roman type in page form.
The automatic inlet of cold water to the hot water system from the main house tank or other source is controlled by a ball valve, which is so fixed as to allow the water to rise no more than an inch above the bottom of the tank, thus leaving the remainder of the space clear for expansion.
The idea of automatic telephony is to substitute for the operator of the manual exchange an electromechanical or other switching system, which, controlled in its movement by the action of the subscriber, will automatically select, connect and disconnect circuits as desired.