attracted towards the tuning-fork. If the tuning-fork is itself suspended, it is seen to be attracted towards any body placed near it.
Sir W. Thomson has shown that this action can in all cases be explained by the general principle that in fluid motion the average pressure is least where the average energy of motion is greatest. Now, the wave motion is greatest nearest the tuning-fork, the pressure is therefore least there ; and the suspended body being pressed unequally on opposite sides, moves from the side of greater pressure to the side of less pressure, that is towards the tuning-fork. He has also succeeded in producing repulsion in the case of a small body lighter than the surrounding medium.
It is remarkable that of the three hypotheses, which go some way towards a physical explanation of gravitation, every one involves a constant expenditure of work. Le Sage's hypothesis of ultramundane corpuscules does so, as we have shown in the article Atom: That of the generation or absorption of fluid requires, not only constant expenditure of work in emitting fluid under pressure, but actual creation and destruction of matter. That of waves requires some agent in a remote part of the universe capable of generating the waves.
According to such hypotheses we must regard the processes of nature not as illustrations of the great principle of the conservation of energy, but as instances in which, by a nice adjustment of powerful agencies not subject to this principle, an apparent conservation of energy is maintained. Hence, we are forced to conclude that the explanation of the cause of gravitation is not to be found in any of these hypotheses.
ATTWOOD, THOMAS, musical composer, was born in
London in 1767. As one of the boy choristers in the
chapel royal he received his early instruction in music
from Nares and Ayrton. In 1783 he was sent to study
abroad at the expense of the Prince of Wales, who had
been favourably impressed by his skill as a performer on
the harpsichord. After spending two years at Naples,
Attwood proceeded to Vienna, where he became a favourite
pupil of Mozart. On his return to London he held for a
short time an appointment as one of the chamber musicians
to the prince of Wales. In 1795 he was chosen organist
of St Paul s, and in the following year he succeeded Dr
Dupuis as composer to the chapels royal. His court con
nection was further confirmed by his appointment as
musical instructor to the duchess of York and afterwards
to the princess of Wales. For the coronation of George
IV. he composed the anthem, The King shall Rejoice,
a work of high merit. The king, who had neglected him
for some years on account of his connection with the
princess of Wales, now restored him to favour, and in 1821
appointed him organist to his private chapel at Brighton.
Soon after the institution of the Royal Academy of Music,
Attwood was chosen one of the professors. He wrote the
anthem, Lord, grant the King a Long Life, which was
performed at the coronation of William IV., and he was
composing a similar work for the coronation of Queen
Victoria when he died (March 24, 1838). Attwood s com
positions are favourable specimens of the English school.
His services and anthems were published in a collected
form after his death by his pupil Walmesley, and are fre
quently used in cathedral worship. Of his secular composi
tions several songs and glees are well known and popular.
The operas which he composed in early life are now almost
forgotten, belonging, as they do, to a period when English
music was at its lowest ebb.
ATWOOD, GEORGE, an author celebrated for the accuracy
of his mathematical and mechanical investigations, and
considered particularly happy in the clearness of his explana
tions, and the elegance of his experimental illustrations,
was born in the early part of the year 1746. He was
educated at Westminster school, to which he was admitted
in 1759. Six years afterwards he was elected off to Trinity
College, Cambridge. He took his degree of ^Bachelor of
Arts in 1769, with the rank of third wrangler and first
Smith s prizeman. These distinctions were amply sufficient
to give him a claim to further advancement in his own
college. In due time he obtained a fellowship, and was
afterwards one of the tutors of the college. He became
Master of Arts in 1772, and in 1776 was elected a fellow
of the Royal Society of London. In the year 1784 he
ceased to reside at Cambridge, and soon afterwards received
from Mr Pitt a patent office, which required but little of
his attendance, and enabled him still to devote a consider
able portion of his time to his special studies. He died in
1807. Atwood s published works, exclusive of papers
contributed to the Philosophical Transactions, for one of
which he obtained the Copley medal, are as follows : (1.)
Analysis of a Course of Lectures on the Principles of
Natural Philosophy, Cambridge, 1784. (2.) Treatise on the
Rectilinear Motion and Rotation of Bodies, Cambridge,
1784, which contains a good account of the elementary
principles of mechanics, though it is deficient in the appli
cation of higher mathematical analysis. It also gives some
interesting experiments, by means of which mechanical
truths can be ocularly exhibited and demonstrated, and
describes the machine, since called by Atwood s name,
for verifying experimentally the laws of simple acceleration
of motion. (3.) Review of the Statutes and Ordinances of
Assize which have been established in England from the 4th
year of King John, 1202, to the 37th of his present Majesty,
London, 1801, a work of some historical research. (4.)
Dissertation on the Construction and Properties of Arches,
London, 1801, with supplement, pt. i. 1801, pt. ii. 1804,
an elaborate and, in its time, valuable work, though it is
now completely superseded.
ATYS, ATTIS, or ATTES, in the Phrygian and Lydian
Mythology, a youth beloved for his beauty by the goddess
Rhea, there called Agdistis. Like Adonis, he was a per
sonification of the changes in nature, from the beauty of
spring and summer to the severity and darkness of winter.
The story, as told at Pessinus, the centre of the worship
of the goddess, was that she had born to Zeus a being both
male and female ; that the gods, displeased, had transformed
this being into a tree, from the fruit of which the daughter
of the river-god Sangarius bore a boy, who grew up
among herdsmen marvellous in his beauty, so as to win the
love of Agdistis. This was Atys, and he was about to be
married to the king s daughter of Pessinus, when the god
dess appeared among the guests, terrified them, and caused
Atys to run to the woods, where he maimed himself and
was transformed into a pine tree ; from his blood sprang
violets. Agdistis begged Zeus to restore him, but he could
only assure her that the youth would never decay, and that
his hair would always grow. She conveyed the pine to her
cave at Pessinus, and gave herself up to grief.
AUBAGNE, a town of France, in the department of Bouches-du-Rhone, with a population of 7408, who carry on the manufacture of wine, pottery, leather, coarse cloth, &c. The only remarkable monument is a fountain to the memory of the Abbé Barthelemy, whose family was long connected with the town.
AUBE, a department of France, bounded on the N . by
the department of Marne, N.W. by Seine-et-Marne, W.
