Motions Of Sun Research Articles

Secular terms and fluctuations in the motions of the sun and the moon

Secular terms and fluctuations in the motions of the sun and the moon

The Concrete Devices of Structural

In the teaching of science it is common practice to use models and devices which make it possible for the pupils to see with their own eyes all those usually “invisible” objects which they want to study. A model of the solar system, for instance, allows the pupils to discover the relative movements of earth, sun, and moon in a simple set-up which shows the structure of the system. Even abstract principles and formulas become clear when they arc illustrated by experiments which the pupils carry out with structura lly correct concrete devices.

Dr. H. Spencer Jones, F.R.S

DR. HAROLD SPENCER JONES, His Majesty's Astronomer at the Cape, has been appointed Astronomer Royal in succession to Sir Frank Dyson, and will commence his duties next March. Dr. Spencer Jones is well-known at Greenwich, for he went there in 1913 and served for ten years as chief assistant. The study of optics is one of his favourite pursuits; during the War he gave much time to testing lenses that were required for military purposes. He observed the solar eclipse of 1914 in Russia, and went to Christmas Island for that of 1922, but it was cloudy. He has been ten years at the Cape and has made a very careful study of the motions of sun, moon and planets; he has discussed the lunar elements both from the meridian observations and from occupations, of which a great number have been observed. He is also a keen spectroscopist, and has contributed many papers on Nova Pictoris, deducing its distance from the rate of expansion of the nebulous envelopes. The heliometer measures of the planets, inaugurated by Sir David Gill, have been continued, and will shortly be published. Prof, de Sitter testified, in his discussion of the satellites of Jupiter, to the value of the results obtained with that instrument. A reversible transit-circle has been in use at the Cape for many years, of somewhat similar type to the new Greenwich instrument; experience with it will doubtless be of service to Dr. Spencer Jones at Greenwich. He will also find the new Yapp reflecting telescope nearly complete.

Weather Influences in the British Isles

THE sun is the only source of terrestrial weather in the sense that the difference between the amount of solar radiation received in different latitudes is the driving force of the atmospheric circulation. The complexity of the earth's surface combined with its rotation about an axis introduces corresponding complexities into this circulation, but H. H. Clayton considers that “if there were no variation in solar radiation the atmospheric motions- would establish a stable system with exchanges of air between equator and pole and between ocean and land, in which the only variations would be daily and annual changes set in operation by the relative motions of earth and sun; the existing changes we call weather have their origin chiefly, if not entirely, in the variation of solar radiation.” It has been found that some parts of the earth, especially the tropics, respond readily to these solar variations, while in other parts the solar variation is almost completely masked by secondary modifications. Hence we may classify weather influences into two classes: solar, in which the influence of solar variation is directly recognisable, and terrestrial, depending on causes which at first sight are entirely due to the influence of the land, sea, or atmosphere. These two classes shade into each other, with no definite line between them.