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win and hydrometeors, such as are usual in observatories of the first order; together also with apparatus, such, for example, as Seismic instruments, which is pretty certain to be procured before long. I propose also to provide a small room for the Electrograph, which will be referred to further in connexion with observations of atmospheric electricity. I have added, at Mr. BOWDLER's suggestion, an upper storey, to be appropriated as quarters for the Director. I recommend that the building be constructed of red bricks, the walls of the lower storey being made 1 ft. 9 in. thick, and those of the upper storey 1 ft. 2 in. thick.
So lately as last February, Dr. WARREN DE LA RUE furnished the Colonial Office with a list of the instruments necessary for these purposes in a first-class meteorological observatory. The list comprises a Barograph, a Thermograph, an Anemograph, a Rain-gauge, a Sunshine Recorder, and an Electrograph; together costing about £397.
Of these, the Barograph, or self-recording barometer, will be accommodated in the Magnetic Room in the basement, to be presently described.
For the Thermograph—i.e., self-registering (photographic) dry and wet bulb thermometers—a special hut and shed will have to be put up in the grounds of the observatory. This may, however, be left until the instruments arrive.
In laying out the building on the ground, it will be important to obtain accurate orientation, for which purpose I suggest that Polaris be observed with a theodolite at one of its culminations, and a meridian line carefully marked at the observation. The transit-room will need vertical shutters about two feet wide, opening in the north and south walls from a height of four feet above the floor and extending to the roof; also roof-doors of the same width, so that there may be a clear view of the meridian from the south to the north horizon.
The rooms should be 15 feet high, from floor to ceiling, and the roof be made as flat as possible, in order that it may be utilised for some of the meteorological apparatus.
Especial care must be given to protection of the building against lightning, for which purpose one conductor should be placed at each angle of the main block, and the points carried at least eight feet above the parapet, the earth ends being sunk below ground until permanently damp soil is reached.
Piers, isolated from contact with the surrounding soil or any parts of the building, will be needed for the transit-instrument, the electrograph, the collimator, and each of the two clocks. These should be built of red bricks, in cement, and be carried down to firm ground, at a depth of not less than four feet in any case, there resting on good foundations of cement concrete.
A building on a plan somewhat as shown in the accompanying tracing will probably answer well for the present purposes of the Observatory. If at a future time it should be decided to increase the equipment, the east and west wings could be extended so as to accommodate a Photoheliograph for the record of sun-spots, as suggested by His Excellency the Governor, and an Equatorial telescope.
It would be necessary, in this case, to raise the equatorial sufficiently high to obviate any serious interruption of the sky view by the upper storey of the main block; and, for architectural symmetry, the photoheliograph might be similarly raised.
A building of the kind above suggested would probably cost, with piers, &c., about $10,500, to which $500 must be added for furniture and fitments. A small additional building, to contain quarters for a caretaker, servant and coolies, with a store, workshop, kitchen and other offices, and connected with the main edifice by a covered way, would cost say $2,400 more.
II. Meteorology.
The proposal to establish a meteorological branch of the observatory, under skilled management and supplied with the best modern apparatus, commands approval for two reasons.
In the first place, as Dr. DE LA RUE has indicated, such an institution will furnish the science with valuable and much-needed data, from a locality well suited for the observation and collection of facts appertaining to certain phenomena of special interest.
Secondly, it cannot fail to have a direct and practical value, as being the means of affording security, by its predictions and weather warnings, to life and property, in seas navigated by vast numbers of native and foreign vessels, but subject during four or five months of the year to rotatory storms of appalling violence and danger.
The Anemograph, or self-recording Anemometer, is an instrument the best and newest forms of which are constructed to register continuously the direction, pressure and velocity of the wind. A small turret, to carry the vane, &c., for the instrument, of whatever pattern, may be erected centrally over the front verandah roof of the main building, and the spindle be carried through the roof to the registering apparatus placed in a small chamber or compartment on the upper verandah, as shown in the drawing.
The Rain-gauge, to judge from the high price (£60) set against it in the list, is doubtless a self-recording instrument, or pluviograph.
The Sunshine Recorder is a contrivance for marking and measuring the duration of sunshine. The instrument in use at Greenwich consists of a solid glass ball four inches in diameter, supported in a hollow hemispherical bowl of three inches' radius.
The Electrograph of Dr. DE LA RUE's list, though not described, is doubtless a THOMSON'S Quadrant Electrometer, fitted for photographic self-registration. I have provided a small room for it on the ground floor of the main building, the window of which can be darkened to the extent required.
The whole of the above are autographic instruments, and need only occasional attention, for changing the record-sheets, pointing the pencils, &c.
The second branch of work appertaining to the Meteorological Department will be the observation and collection, as far as possible, of facts and phenomena relating to typhoons, both for the protection of marine interests and for the purpose of contributing bit by bit to our knowledge of a subject at present but little understood.
For weather warnings, the telegraphic cables connecting this port with others on the coast, and with Manila, will furnish most valuable aid. Past observations seem to show that the typhoons which sweep the Southern China sea for the most part originate in a region the centre of which is situated about a thousand miles (in round numbers) to the south and east of the Philippines.
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