PET 
siciaii to the army in Ireland ; as also to 
three Lord Lieutenants, successively, Lam- 
bert, Fleetwood, and Henry Cromwell. 
In Ireland he acquired a great fortune, but 
not without suspicions and charges of unfair 
practices in his offices. After the rebellion 
Was over in Ireland, he was appointed one 
of the Commissioners for dividing the for- 
feited lands to the army who su|)pressed it. 
When Henry Cromwell became Lieutenant 
of that kingdom, in 1655, he appointed 
Dr. Petty his Secretary, and Clerk of the 
Council : he likewise procured him to be 
elected a burgess for West Loo in Cornwall, 
in Richard Cromwell’s parliament, which 
met in January, 1658. But, in March fol- 
lowing, Sir Hierom Sankey, member for 
Woodstock in Oxfordshire, impeached him 
of high crimes and misdemeanors in the 
execution of his office. This gave the doc- 
tor a great deal of trouble, as he was sum- 
moned before the House of Commons; and 
notwithstanding the strenuous endeavours 
of his friends, in their recommendations of 
him to Secretary Thurloe, and the defence 
he made before the House, his enemies 
procured his dismission from his public em- 
ployments, in 1659. He then retired to 
Ireland till the restoration of King Charles 
the Second ; soon after which he came into 
Englaml, where he was very graciously 
received by the King, resigned his profes- 
sorship at Gresham College, and was ap- 
pointed one of the Commissioners of the 
Court of Claims. Likewise, April the 11th, 
1661, he received the honour of knight- 
hood, and the grant of a new patent, con- 
stituting him Surveyor General of Ireland, 
and was chosen a member of parliament 
there. 
Upon the incorporating of the Royal 
Society, he was one of the first members, 
and of its first council. And though he had 
left off the practice of physic, his name was 
continued as an honorary member of the 
College of Physicians in 1663. About this 
time he invented his double-bottomed ship, 
to sail against wind and tide, and after- 
wards presented a model of this ship to the 
Royal Society ; to whom also, in 1665, he 
communicated “ A Discourse about the 
Building of Ships,” containing some curious 
secrets in that art. But, upon trial, find- 
ing his ship failed in some respects, he at 
length gave up that project. 
In 1666, Sir William drew up a treatise, 
called “Verbum Sapienti,” containing an 
account of the wealth and expenses of Eng- 
land, and the method of raising taxes in 
PEU 
tlie most equal manner. He was well 
acquainted with the general principles of 
political arithmetic, and studiously promot- 
ed many projects highly useful to his 
country. It must, however, be admitted 
that he was equally attentive to his own 
interests. Thus, at sixty, he writes that his 
thoughts were fixed upon improving his 
lands in Ireland, and to promote the trade 
of iron, lead, marble, fish, &c. of which his 
estate is capable. As for studies and ex- 
periments, “ I think now,” says he, “ to 
confine the same to the anatomy of the 
people, and political arithmetic ; as also 
the improvement of ships, land carriages, 
guns, and pumps, as of most use to man- 
kind.” He died in December, 1687, leav- 
ing behind him wealth to the amount of about 
15,000Z. per annum. His works were very 
numerous, some of which are well known, 
and frequently referred to by authors in the 
present day. 
PETTY bag, an office in Chancery, tlie 
three clerks of which record the return of 
all inquisitions out of every county, and 
make all patents of comptrollers, gaugers, 
customers, &c. 
PETUNSE, in the arts, one of the prin- 
cipal substances made use of in the manu- 
facture of porcelain ; the other is kaolin. 
Petunse consists of 
Silex 74 
Alumina 14.5 
Lime 5.5 
94.0 
Kaolin consists of 
Silex 74 
Alumina 16.5 
Lime 2 
Water 7 
99.5 
Therefore the two together consist of si- 
lex and alumina, with less than 5 per cent 
of lime. See Porcelain. 
PEUCEDANUM, in botany, sulphur- 
loort, a genus of the Pentandria Digynia 
class and order. Natural order of Umbel- 
latae, or Umbelliferaj. Essential character : 
fruit ovate, striated on both sides, girt with 
a membrane ; involucres very short. There 
are eleven species, of which P. officinale, 
common sulphur wort, has a perennial root, 
dividing into many strong fibres, running 
deep into the ground ; leaves from the root 
branching into five' parts, and these again 
