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THE HONGKONG GOVERNMENT GAZETTE, 3RD SEPTEMBER, 1881. 809
clous, gonds, serrures, charnières, venues d'Europe, ne pas se fier aux Chinois pour cela: tous leurs 'objets de cuivre contiennent une grande proportion de fer. Tout le cuivre qui est entré dans notre "salle magnétique, et principalement tout ce que nous avons été obligé de faire fabriquer par des ouvriers "Chinois, à été essayé au magnétomètre avant d'être accepté, et rejeté invariablement dès qu'il produisait
sur l'aimant une déviation de quelques minutes d'arc à un pied de distance."
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The Barograph, it may also be remarked, must, if possible, have no iron about it, as it will be mounted in the same chamber with the Magnetograph. The instrument-pillars, which should be capped with slabs of slate or marble, may be made from the same material as that of the building itself; but they cannot be built until the instruments themselves, or their exact dimensions, have been received.
For protection against lightning, a single conductor, carried by a post 25 feet high, erected any- where near the building, will answer,
For the Dip-circle, a small pavilion and pier will have to be erected, in a position well removed from the other magnets, such as the ground outside the astronomical building. This, however, as well as the provision, also above ground, to be made for the Unifilar Magnetometer, may be considered later on.
In the meantime, there will be nothing to prevent the two main buildings from being proceeded with as soon as the working drawings and estimates can be prepared.
IV. Tidal Observations.
There is one instrument which, though referred to in His Excellency the Governor's despatch already quoted from, has not yet been mentioned in this report, and which might with advantage be added to the outfit, namely, a Tide-gauge, for the purpose of determining the laws of the tides at Hongkong, certain phenomena of which, such as the diurnal and other inequalities, are peculiar and, I believe, but little known or understood. An autographic tide-gauge might be set up in a chamber constructed for the purpose near the Tsim-shá-tsui Police Station, and attended to each day by the man in charge of the Time-Ball and Weather-Signals. Such a gauge, of Sir W. THOMSON'S pattern, would cost about £95.
Admiral RYDER suggested, in 1877, that an automatic Tide-gauge should be set up at Cape D'Aguilar, and placed in charge of the lighthouse-keeper there. This is most desirable, as a means of establishing the direction and rate of the tides, and I recommend that it be carried out unless the engineering difficulties prove too serious, in which case a suitable spot might perhaps be found on one of the headlands nearer to Stanley. A less expensive gauge, of NEWMAN'S pattern, and costing about £50, would serve for this station.
V.-Staff.
Notwithstanding that so large a proportion of the various intruments will be of self-registering patterns, the routine work of the observatory will, nevertheless, be very considerable. Even auto- graphic instruments require periodic attention, most of them at least once daily. Time-determinations should be made certainly three or four times a week, and these necessitate a considerable amount of observing by night and computing by day. Frequent periodic magnetic observations for absolute values, which are tedious, difficult and highly complicated, will also have to be made and computed. Constant attention must be given to the adjustments of the extensive and miscellaneous apparatus, to winding and regulating clocks, ascertaining the errors of the instruments, and keeping all clean and in good order. A good deal of extra work will also devolve upon the Department during several months of the year, in collecting information respecting typhoons.
The regular clerical labour will consist mainly of entering the observations and calculations in the books and forms for that purpose, transcribing and filing the automatic records, compiling weather exchanges and storm data, abstracting typhoon-logs, preparing periodical reports, accounts, &c., and general correspondence.
The Director of the Establishment should be, if possible, some one recommended by the Astronomer-Royal. No one could be more desirable than an ex-assistant of the Royal Observatory. I do not think we can expect to get a competent person for less than $300 per mensem. He should have, as First assistant, a practical man, chosen with great care a man able to observe and compute, acquainted with the mechanical details of the instruments, and competent to execute, or at least direct, ordinary repairs. An assistant of this kind could probably be got from amongst the non-commissioned officers of the Ordnance Survey Companies of the Corps of Royal Engineers, a very valuable body of men. He should receive a salary of $120 per mensem. To the Royal Engineers we may also look for the Second assistant, who should be a good photographer, and be deputed to attend specially to the Magnetic instruments. Arrangements might, no doubt, be made to procure for him a month's training at the Greenwich Observatory in the routine of the magnetic work. He might be paid $75 per
mensem.