for miles over the ground at the rate of ten or twenty miles
an hour, catching now and then in hedges, ditches, roots of
trees, &c.; and, after giving the balloon a terrible jerk,
breaking loose again, till at length some obstruction, such
as the wooded bank of a stream, affords a firm hold. This
danger, however, has been much reduced by the use of the
``ripping-cord,'' which enables a panel to be ripped open and
the balloon to be completely deflated in a few seconds, just
as it is reaching the earth. But even a very rough descent
is usually not productive of any very serious consequences;
as, although the occupants of the car generally receive many
bruises and are perhaps cut by the ropes, it rarely happens
that anything worse occurs. On a day when the wind is light
(supposing that there is no want of ballast) nothing can be
easier than the descent, and the aeronaut can decide several
miles off on the field in which he will alight. It is very
important to have a good supply of ballast, so as to be able
to check the rapidity of the descent, as in passing downwards
through a wet cloud the weight of the balloon is enormously
increased by the water deposited on it; and if there is no ballast
to throw out in compensation, the velocity is sometimes very
great. It is also convenient, if the district upon which
the balloon is descending appear unsuitable for landing, to
be able to rise again. The ballast consists of fine baked
sand, which becomes so scattered as to be inappreciable
before it has fallen far below the balloon. It is taken
up in bags containing about 1/2 cwt. each. The balloon at
starting is liberated by a spring catch which the aeronaut
releases, and the ballast should be so adjusted that there
is nearly equilibrium before leaving, else the rapidity of
ascent is too great, and has to be checked by parting with
gas. It is almost impossible to liberate the balloon in such
a way as to avoid giving it a rotary motion about a vertical
axis, which continues during the whole time it is in the
air. This rotation makes it difficult for those in the car to
discover in what direction they are moving; and it is only by
looking down along the rope to which the grapnel is suspended
that the motion of the balloon over the country below can be
traced. The upward and downward motion at any instant is at once
known by merely dropping over the side of the car a small piece
of paper: if the paper ascends or remains on the same level or
stationary, the balloon is descending; while, if it descends,
the balloon is ascending. This test is exceedingly delicate.
REPERENCES.--Tiberius Cavallo, Treatise on the Nature
and Properties of Air and other permanently Elastic Fluids
(London, 1781); Idem, History and Practice of Aerostation
(London, 1785); Vincent Lunardi, Account of the First Aerial,
Voyage in England, in a Series of letters to his Guardian
(London, 1785); T. Forster, Annals of some Remarkable aerial
and alpine Voyages (London, 1832); Monck Mason, Aeronautica
(London, 1908; John Wise, A System of Aeronautics,
comprehending its Earliest Investigations (Philadelphia,
1850); Hatton Tumor, Astra Castra, Experiments and Adventures
in the Atmosphere (London, 1863); J. Glaisher, C. Flammarion,
W. de Fonvielle and G. Tissandier, Voyages aeriens (Paris,
1870) (translated and edited by James Glaisher under the title
Travels in the Air (London, 1871); O. Chanute, Progress
in Flying Machines (New York, 1894); W. de Fonvielle, Les
Ballons sondes (Paris, 1899); Idem, Histoire de la navigation
aerienne (Paris, 1907); F. Walker, Aerial Navigation
(London, 1902); J. Lecornu, La Navigation aerienne (Paris,
1903); M. L. Marchis, Lecons sur la navigation aerienne
(Paris, 1904), containing many references to books and
periodicals on pp. 701-704; Navigating the Air (papers
collected by the Aero Club of America) (New York, 1907); A.
Hildebrandt, Airships past and present (London, 1908).
1 Mr Tytler contributed largely to, and, indeed,
appears to have been virtually editor of, the second
edition (1778-1783) of the Encyclopaedia Britannica.
AEROTHERAPEUTICS, the treatment of disease by atmospheric
air: a term which of late has come to be used somewhat more
loosely to include also pneumotherapeutics, or the treatment
of disease by artificially prepared atmospheres. The physical
and chemical properties of atmospheric air, under ordinary
pressure or under modified pressure, may be therapeutically
utilized either on the external surface of the body, on the
respiratory surface, or on both surfaces together. Also
modifications may be induced in the ventilation of the lungs by
general gymnastics or respiratory gymnastics. The beneficial
effects of air under ordinary pressure are now utilized in
line open-air treatment of phthisical patients, and the main
indications of benefit resulting therefrom are reduction
of the fever, improvement of appetite and the induction of
sleep. The air, however, may be modified in composition or in
temperature. Inhalation is the most common and successful
method of applying it--when modified in composition--to the human
body. The methods in use are as follows: (1) Inhalation
of gases, as oxygen and nitrous oxide. The dyspnoea and
cyanosis of pneumonia, capillary bronchitis, heart failure,
&c., are much relieved by the inhalation of oxygen; and
nitrous oxide is largely used as an anaesthetic in minor
operations; (2) Certain liquids are used as anaesthetics,
which volatilize at low temperatures, as chloroform and
ether. (3) Mercury and sulphur, both of which require heat for
volatilization, are very largely used. In a mercurial or
sulphur bath, the patient, enveloped in a sheet, sits on a
chair beneath which a spirit lamp is placed to vaporize the
drug, the best resuits being obtained when the atmosphere is
surcharged with steam at the same time. The vapour envelops
the patient and is absorbed by the skin. This method is
extensively used in the treatment of syphilis, and also for
scabies and other parasitic affections of the skin. (4) Moist
inhalations are rather losing repute in the light of modern
investigations, which tend to show that nothing lower
than the larger bronchial tubes is affected. Complicated
apparatus has been devised for the application, although
a wide-mouthed jug filled with boiling water, into
which the drug is thrown, is almost equally efficacious.
Artificial atmospheres may be made for invalids by
respirators which cover the mouth and nose, the air being
drawn through tow or sponge, on which is sprinkled the
disinfectant to be used. This is most valuable in the
intensely offensive breath of some cases of bronchiectasis.
The air may be modified as to temperature. Cold air at
32--33 deg. F. has been used in chronic catarrhal conditions of
the lungs, with the result that cough diminishes, the pulse
becomes fuller and slower and the general condition improves.
The more recent observations of Pasquale di Tullio go far to
show that this may be immensely valuable in the treatment of
haemoptysis. The inspiration of superheated dry air has been the
subject of much investigation, but with very doubtful results.
Hot air applied to the skin is more noteworthy in its
therapeutic effects. If a current of hot air is directed
upon healthy skin, the latter becomes pale and contracts
in consequence of vaso-constriction. But if it is directed
on a patch of diseased skin, as in lupus, an inflammatory
reaction is set up and the diseased part begins to undergo
necrosis. This fact has been used with good results in lupus,
otorrhoea, rhinitis and other nasal and laryngeal troubles.
Lastly the air may be either compressed or rarefied. The
physiological effects of compressed air were first studied in
diving-bells, and more recently in caissons. Caisson workers
at first enjoy increased strength, vigour and appetite; later,
however, the opposite effect is produced and intenbe debility
supervenes. In addition, caisson workers suffer from a series
of troubles which are known as accidents of decompression. (See
CAISSON DISEASE.) But, therapeutically, compressed air has
been utilized by means of pneumatic chambers large enough to
hold one or more adults at the time, in which the pressure of
the atmosphere can be exactly regulated. This form of treatment
has been found of much value in the treatment of emphysema, early
pulmonary tuberculosis (not in the presence of persistent high
temperature, haemorrhage, softening or suppuration), delayed
absorption of pleural effusions, heart disease, anaemia and
chlorosis. But compressed air is contra-indicated in advanced
tubercle, fever, and in diseases of kidneys, liver or intestines.
Rarefied air was used as long ago as 1835, by V. T. Junod,
who utilized it for local application by inventing the Junod
Boot. By means of this the blood could be drawn into any
part to which it was applied, the vessels of which became
gorged with blood at the expense of internal organs. More
recently this method of treatment has undergone far-reaching
developments and is known as the passive hyperaemic treatment.
There are also various forms of apparatus by means of which
air at greater or lesser pressures may be drawn into the
lungs, and for the performance of lung gymnastics of various
kinds. Mr Ketchum of the United States has invented one which
is much used. A committee of the Brompton Hospital, London,
investigating its capabilities, decided that its use brought
about (1) an increase of chest circumference, and (2) in cases
of consolidation of the lung a diminution in the area of dulness.
AERTSZEN (or AARTSEN), PIETER (1507-1573), called
``Long Peter'' on account of his height, Dutch historical
painter, was born and died at Amsterdam. When a youth he
distinguished himself by painting homely scenes, in which he
reproduced articles of furniture, cooking utensils, &c., with
marvellous fidelity, but he afterwards cultivated historical
painting. Several of his best works---altar-pieces in
various churches---were destroyed in the religious wars of the
Netherlands. An excellent specimen of his style on a small
scale, a picture of the crucifixion, may be seen in the Antwerp
Museum. Aertszen was a member of the Academy of St Luke,
in whose books he is entered as Langhe Peter, schilder.
Three of his sons attained to some note as painters.
AESCHINES (389-314 B.C.), Greek statesman and orator, was
born at Athens. The statements as to his parentage and early
life are conflicting; but it seems probable that his parents,
though poor, were respectable. After assisting his father
in his school, he tried his hand at acting with indifferent
success, served with distinction in the army, and held
several clerkships, amongst them the office of clerk to the
Boule. The fall of Olynthus (348) brought Aeschines into the
political arena, and he was sent on an embassy to rouse the
Peloponnesus against Philip. In 347 he was a member of the
peace embassy to Philip of Macedon, who seems to have won him
over entirely to his side. His dilatoriness during the second
embassy (346) sent to ratify the terms of peace led to his
accusation by Demosthenes and Timarchus on a charge of high
treason, but he was acquitted as the result of a powerful
speech, in which he showed that his accuser Timarchus had, by
his immoral conduct, forfeited the right to speak before the
people. In 343 the attack was renewed by Demosthenes in his
speech On the False Embassy; Aeschines replied in a speech
with the same title and was again acquitted. In 339, as one
