A manual of scientific enquiry, prepared for the use of her majesty's navy and adapted for travellers in general, ed. by sir J.F.W. Herschel

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Pagina 301 - There is every reason to consider it established that an earthquake is simply "the transit of a wave or waves of elastic compression in any direction, from vertically upwards to horizontally in any azimuth, through ike crust and surface of the earth, from any centre of impulse, or from more than one, and which may be attended with sound and tidal waves, dependent upon the impulse and upon circumstances of position as to sea and land.
Pagina 90 - ... if the amount is large, the heeling error is corrected by the application of a vertical magnet. The whole process is described, and all the mathematical formula and arithmetical processes, and a number of convenient graphic methods, are given in the "Admiralty Manual for ascertaining and applying the Deviations of the Compass caused by the Iron of a Ship.
Pagina 71 - Mistakes and errors have often been produced in tide observations by supposing that the turn of the tide stream is the time of high water. But this is not so. The turn of the stream generally takes place at a different time from high water, except at the head of a bay or creek. The stream of flood commonly runs for some time, often for hours, after the time of high water. In the same way, the stream of ebb runs for some time after low water.
Pagina 115 - Of the Times of Observation and Registry. Meteorological observations should be made and registered daily, at stated and regular hours. In fixing on these, some sacrifice of system must of necessity be made to the convenience and habits of the observer. The best hours in a scientific...
Pagina iii - ... instructions for observation and for record in various branches of science. Their Lordships do not consider it necessary that this Manual should be one of very deep and abstruse research. Its directions should not require the use of nice apparatus and instruments : they should be generally plain, so that men merely of good intelligence and fair acquirement may be able to act upon them ; yet, in pointing out objects, and methods of observation and record, they might still serve as a guide to officers...
Pagina 267 - Hence, on whatever coast ancient ice-action may be discovered, the limit of latitude towards the tropics at which it ceases ought to be carefully investigated. Observations are much wanted on the west coast of North America and the east coast of Asia ; and again in New Zealand and other islands of the Southern Ocean. The period of the ice-action is pretty well ascertained in Europe and North America, and a...
Pagina 114 - ... which consists in noting at stated hours of every day the readings of all the meteorological instruments at command, as well as all such facts or indications of wind and weather as are susceptible of being definitely described and estimated without instrumental aid. Occasional observations apply to occasional and remarkable phenomena, and are by no means to be neglected ; but it is to the regular meteorological register, steadily and perseveringly kept throughout the whole of every voyage, that...
Pagina 143 - The usual course of periodical winds, or such as remarkably prevail during certain seasons, with the law of their diurnal progress, both as to direction and intensity — at what hours, and by what degrees, they commence, attain their maximum, and subside, and through what points of the compass they run in so doing.
Pagina 304 - ... rapidly: the first due to the originating normal wave; the second to the transversal waves vibrating at right angles to it. If we can find the point of the surface vertically over the origin, and the direction of emergence of the shock at a distant point, or the angles of emergence at two distant points, neither of which is vertically over the origin—ie, in one' coseismal line—we can find the depth of the origin from the surface by methods p6inted out in Mr. Mallet's Fourth Report on Facts...
Pagina 127 - ... and broken off, so as to leave the end open. The other end of the cylinder is closed by a silver or silver-plated cap, cemented on it, and furnished with a screw, also of silver, passing through a collar of waxed leather, which is pressed into forcible contact with its thread, by a tightening screw of large diameter enclosing it, and working into the silver cap, and driven home by the aid of a strong steel key or wrench, which accompanies the instrument. The...

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