HALES, 
that of Farringdon, in Hampshire. He 
then married the daughter of a clergyman, 
who died after two years, leaving no issue. 
Henceforth he lived entirely as a single 
man, devoting himself entirely to science, 
and objects of public utility. In 1717 he 
was elected a member of the Royal Society, 
and in the following year he read before 
that body an account of some experiments 
concerning the effect of the sun’s heat in 
raising the sap in vegetables. The farther 
prosecution of these experiments gave rise 
to an excellent work published in 1727, 
entitled “ Vegetable Statics, or an ac- 
count of some Statical Experiments on 
the Sap of Vegetables; being an Essay 
towards a Natural History of Vegetation : 
also, a Specimen of an Attempt to Analyse 
the Air by a variety of Chemico-Statical 
Experiments, which were read at several 
Meetings before the Royal Society,” 8vo. 
This piece is justly esteemed a model of 
experimental investigation. Haller charac- 
terizes it as “ liber exirnus, cujus paucissimos 
habemus aemulos qui toties potius legi volet, 
quam decerpi.” It begins by ascertaining 
the vast quantity of watery humour per- 
spired by plants, sometimes equalling their 
whole weight in a single day. It then spe- 
cifies the power with which they attract 
the nutritious juice through their capillary 
tubes, and considers the lateral motion of 
this juice from trunk to branches, and vice 
versa. It disproves any proper circulation 
of this fluid, but establishes its ascent dur- 
ing the day, and descent during the night. 
The leaves are proved to be inspiratory or- 
gans, both of air and water. There are 
besides a number of curious remarks upon 
the vegetable system, as well as upon the 
constitution of atmospherical air, into which 
he was one of the experimental enquirers. 
His experiments upon air relate indeed 
solely to its generation and absorption^ its 
elastic and non-elastic states, arid do not 
proceed to the discovery of any of those 
species of air or gases which have so much 
engaged the attention of modern philoso- 
phers, though they manifestly led to such 
discoveries. A second edition of this work 
appeared in 1731, and in 1733 he published, 
as a kind of sequel to it, his “ Statical Es- 
says, containing Haemastatics ; or an Ac- 
count of some Hydraulic and Hydrostatical 
Experiments made on the Blood and Blood- 
vessels of Animals ; also, an Account of 
some Experiments on Stones in the Kidneys 
and Bladder, &c.” In this he discussed 
some fundamental points relative to physio- 
logy, as the force and celerity with which 
the blood is propelled in the arteries, its 
retardation in the capillary vessels, the area 
of the heart, and the weight of blood sus- 
tained by it, the effects of respiration, and 
the alteration of air by breathing, &c. His 
enquiries concerning the urinary calculus 
relates to its chemical composition, and to 
the means of dissolving it ; of which, sug- 
gested by him, is fixed air, or that produced 
by sulphuric acid and fixed alkali in a state 
of effervescence. He also proposes injec- 
tions into the bladder, and gives a contriv- 
ance for that purpose. This subject he 
afterwards pursued more particularly, and 
published an account of some experiments 
on Mrs. Stephens’s celebrated medicines, in 
1740. The reputation of this worthy man 
kept pace writh his useful labours. In 1732 
he was appointed one of the trustees for 
settling a colony in Georgia ; and, in 1733, 
the University of Oxford presented him 
with the degree of D. D. He performed a 
valuable service to the health and morals of 
the poor, by printing, anonimously, “ A 
Friendly Admonition to the Drinkers of 
Gin, Brandy, and other Spirituous Liquors,” 
which has been several times reprinted and 
distributed gratis. In 1739 he printed 
“ Philosophical Experiments on Sea Water, 
Corn, Flesh, and other Substances,” 8vo. 
chiefly intended for the use of navigators. 
A paper on a similar subject, and the solu- 
tion of the stoqe in the bladder obtained 
him, in the same year, the gold medal from 
the Royal Society. One of the most useful 
of Dr. Hales’ invention was that of venti- 
lators for renewing the air in mines, prisons, 
hospitals, aud holds of ships, which he dis- 
closed to the Royal Society in 1741. Some 
years afterwards his machines were fixed on 
the Savoy and Newgate Prisons, to the 
great benefit of the persons confined in 
them, among whom the progress of the gaol- 
fever was much diminished. His plans for 
producing a free circulation of air were 
also applied by him for the cleansing and 
preservation of corn: for the former pur- 
pose he invented a machine called a back- 
heaver, which he described in the Gentle- 
man’s Magazine for 1745 and 1747. His 
attention to medical subjects was farther 
evinced, by a paper read before the Royal 
Society, in describing a method for convey- 
ing liquors into the abdomen after tapping ; 
by some experiments and observations on 
tar-water; and a detection of some falla- 
cious boasts concerning the efficacy of a 
lithontriptic, called the liquid shell. A 
