812
THE HONGKONG GOVERNMENT GAZETTE, 3RD SEPTEMBER, 1881.
upon the earth's magnetic force which are traceable to the heavenly bodies, and which take the form of fluctuations recurring with strict regularity. That such influences do exist was, however, discovered many years ago, and it is now well established that, in addition to certain variations of long period, there are regular diurnal inequalities of the several elements of the magnetic force, varying with the hour of the day, that is to say, with the sun's position. They attain their maxima and minima at the same hours day after day, though some of the times vary slightly at the different seasons and in different years. Besides these solar-diurnal inequalities, small lunar inequalities have also been detected. These are semidiurnal, going through their changes twice in each lunar day, and apparently depending on the moon's position with respect to the meridian.
Again, it has long been known that solar changes affect the earth's meteorological as well as its magnetic conditions. Observers at many stations scattered over the globe have ascertained that years of maximum sun-spots are also years of maximum rainfall, at least upon the land; and that years of minimum sun-spots are years of minimum rain-years in which some countries suffer most heavily from drought and famine. The same axiom holds good with respect to wind, which, like the rain, is most violent in years of powerful solar action. West Indian hurricanes, the cyclones of the Indian Ocean, and the typhoons of this region are most numerous in years of sun-spot frequency, that is to say,
of greatest solar years
The statistics of marine disasters point to the same conclusion. It has also been shown that terrestrial temperature and barometric pressure are influenced more or less directly by changes of solar energy. Of the causes of sun-spot outbreaks very little is yet known, but the Kew observers have traced an interesting apparent connexion between the periodicity of solar spots and the configurations of the planets Jupiter, Venus and Mercury.
in
power.
Another relation which has been clearly established is that between electrical earth-currents and terrestrial magnetism. These have been shown, by long series of observations, to be strictly consen- taneous. Active magnetic energy is invariably accompanied by abnormal earth-currents, or electric storms, and calm magnetic periods are always calm earth-current periods. On the other hand, the electrical state of the air near the earth's surface, though exhibiting definite daily fluctuations, with double maxima and minima, seems to be unaffected by magnetic circumstances. Earth-currents are likewise known to have a well-marked diurnal inequality, with fixed hours of maximum and minimum strength, and to vary their direction with similar or even greater regularity. Quite lately, it has been sought to establish a lunar theory of earth-currents, and to show that their behaviour exhibits a close correspondence with the periods of the lunar ocean tides. Barometric tides of this nature, the result of the Moon's dynamical influence on the atmosphere, have been detected at places near to the equator; and it is possible that these atmospheric movements have something to do, not only with the variations of the earth-currents, but also with the lunar inequalities of the magnetic force to which reference has been made above.
Lastly, the association of earthquakes with earth-currents has been satisfactorily demonstrated. A little consideration of these wonderful links, connecting so many forms of energy, is surely well calculated to stimulate all who are disposed to encourage and aid physical research. Every bit of work well done, no matter how small, is a stone added to the edifice of exact knowledge by means of which scientific men are attacking and gradually elucidating these great physical problems, and working out results which, however dim or even unintelligible they may seem now, are more than likely to prove of the highest practical value in the future.
Hongkong, 17th July, 1881.
H. S. PALMER,
Major, R.E., and F.Ŕ.A.S.
GOVERNMENT NOTIFICATION.-No. 307.
EDUCATION DEPARTMENT.
His Excellency the Governor has been pleased to make the following provisional appointments, from the 1st instant:-
Mr. ALFRED J. MAY to be Principal of the Government Normal School.
Mr. WONG KUN-LÁN to be Assistant Master of the Government Normal School.
Mr. GEO. A. CALDWELL to be an Assistant Master in the Government Central School.
By His Excellency's Command,•
Colonial Secretary's Office, Hongkong, 3rd September, 1881.
M. S. TONNOCHY, Acting Colonial Secretary.
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