Many interesting novelties have been intro duced within the last few years, in respect to clocks and watches.
Trinity Church at Hull is believed to have the largest clock in the world with four dials or faces. Each dial is 13 feet in diameter, and each pair of hands weighs 56 lbs.
A useful kind of kitchen clock was described a few years ago by the late Mr. Loudon. It bad a bell which called the attention of the cook at certain prescribed periods. Whether it were to boil an egg, or to perform any other kind of cooking which required a certain defi nite number of minutes, the cook moved an index hand on the face of a dial ; and when the allotted time had expired, an alarum or bell rang to announce the fact.
Many of our churches and public buildings have clocks of which the faces are illuminated at night. The Horse Guards' clock was thus first illuminated in 1839, by the rays from a bude-light falling on the surface. It has, how ever, been frequently felt that the mode of illuminating public clocks is not such as to enable the hands to be visible for any conside rable distance ; the direction of the hands is the one important point in the indications of a clock ; and if this be made distinct, the illumination of the clock generally may be in considerable part dispensed with. Mr. Hughes of Liverpool introduced a new method in that town in 1844, and published a small pamphlet relating to it. His plan consists in illumina ting three points only ; viz. the centre of the clock, and the outer extremity of each of the two hands. A stream of gas is conveyed into the spindle or shaft on which the hands are fixed, and thence to the hands themselves ; and there are three orifices or jets where this gas is ignited. In the centre is a red light ; at the outer extremity of the short hand is a green light ; and at the outer extremity of the long hand a white light. The white and the green lights revolve with the hands round the dial plate: the white being always the farthest distant from the central stationary red light. A little consideration will show that this is quite sufficient to make the time intel ligible ; for in looking at an ordinary clock or watch, we are morn guided by the directiom taken by the two hands, with respect to tho centre, than the figures towards which the suds of the hands point. It can be seen from
s much greater distance than the ordinary kinds of illuminated clocks ; and if it be at list not quite so intelligible, it might easily so made so by a few illuminated markings or figures round the circumference of the dial.
A curious circumstance is observable at nearly all our railway stations. If a train proceeds eastward or westward, the change of longitude produces a change in the proper time at the successive stations. If the station clocks show time corresponding to their longi tudes, it would make the time-tables very con fused ; and the pocket watch carried by a passenger would never correspond with the station clocks, except at the town from which his watch is adjusted. But if, on the other hand, all the station-clocks shew Greenwich time (which is the plan adopted throughout Great Britain), then those clocks will not and do not correspond with the church-clocks and pocket-watches of the several towns, and much miscalculation of time results. Mr. Pilbrow has suggested an ingenious mode of obviating these difficulties, by having a clock which shall shew double time ; and a clock so suggested has been constructed by Mr. Fairer of Totten ham. The arrangement is very simple dif fering from the common clock only in the construction of the long or minute hand. This hand is shaped like the sector of a circle, cor responding in size or the number of degrees to the number of minutes in the difference between Greenwich time and the time at any particular station. The curved part of the hand is made of glass, so that the figures can be read through it. One edge or corner of the sector will mark Greenwich time, and the other edge the time at the station ; so that the relation between the two will be instantly ob servable.