316 Turkish Preface toa Tranflation of Bonnycaftle’s Aftranomy. | May |; 
the affftance of fome one of the country, 
fkilled in geometry, that by confulung 
him I might make ufe of appropriate 
terms, correct the folecifms, and confirué 
the phrafes according to the true idiom of 
the language, which perfon is Hufein Rif- 
_ky, native of Taman, fecond fub matter 
of the well appointed new mathematical 
academy ; and in concert with him, by 
God’s help, it was tranflated into the 
Turkih language; and folely by dint of 
the good fortune of the King of Kings, to 
whom all princes bow the neck, and by 
the encouragement and protection of his 
Imperial Majefty, which fertilizes and 
brings to maturity, the work is now 
brought to a happy conclufion. Thofe 
readers who have a juft tafte, and right 
Notions of things, will confider, that, ow- 
ing to the frailty of human nature, no 
book but that of Ged alone can be perfeét ; 
therefore if they happen to meet wiih any 
faults er obicurities, we hope they will 
have the guoodnefs to correct and amend 
them. 
t remains to fay, that, befi'es beowing 
the greateft care and attention which lay 
in cur power in the compofition and ar- 
‘rangement of this Tranflation, we have 
alfo made an addition thereto of fome new 
and ufeful propofitions. Several objec- 
tions and critical remarks, which have hi- 
therto efcaped the notice of commentators, 
are placed at the end of the book: there- 
fore thofe ftudents who with to have a true 
idea of the fcience, and of the unexcep- 
tionable principles on which it is founded, 
ought carefully to confult what is there 
written for their inftruétion. So farewel. 
The Firfi Book of the Elements of Geometry. 
Be it known, that every {fcience has its 
fubject, principles, and theorems. 
The fubje& of a fcience is that which 
treats of its eflential properties ; accord- 
ingly the fubject of geometry is magni- 
tude, exifting by the effential properties of 
continued quantity. 
The principles of a fcience are thofe 
things which are requifite for eftablifhing 
the theorems, and thefe are of two kinds. 
The firit kind ere the ideal principles, 
i.e. the definitions of fuch terms as are 
ufed in that fcience. The fecond kind 
are the fyllogiftic principl-s, which arife 
from the arrangement and comparifon of 
the propofitions themfelves. Now if thofe 
propofitions are felf-evident, they are call- 
ed axioms ; but if they are not felfevi- 
dent, yet neverthelefs are eafily and rea- 
{fsnab!y conceived to be poflible, then 
they are called poftulates ; and if fome 
propofitions are admitted with doubt and 
hefitation, until demonttrated in their pro- 
per places, they are called anticipated. pro- 
pofitions; and from thefe anticipated 
propofitions, how much foever others may 
have made ufe of them, yet as they are 
not held in efteem or repute, this book is 
entirely free, . 
The theorems of a fcience are thofe pro- 
pofitions, wherein, by means of the ideal 
and fyllogiftic principles combined, we in- 
veftigate certain properties. 
In geometry the faid propofitions are 
either practical or fpeculative : the prac- 
tical requires the previous conftruction of 
fomething unfinifhed, and afterwards to 
demonftrate it ; the fpeculative requires 
only the demonftration of fomething that 
is already conftrudcted. 
Now as every book whatfoever refts ne- 
ceflarily on its ideal and {fyllogiftic princi- 
ples, therefore this book alfo muf reit on 
the definitions, axioms, and poitulates ; _ 
which being the things requifite in geo- 
metry, we have above explained ; and fo 
God inelp us through. 
Definitions. 
Solid, furface, line, point, &c. &c. &c. 
as inthe original Elements. 
Conclufion of the Notes and Critical Re- 
. marks. 
By the affiftance of the Lord of the 
Univerfe, the work which we had under- 
taken, draws near to a conclufion; and it 
is evident, from the preceding remarks, 
how much the Elements of Euclid have 
been vitiated and fpoilt by unfkilful edi- 
tors. Whoever attentively confiders and 
refle&s on the above blemifhes,; will be 
furprifed and difgufted at the indecent be- 
haviour of thole people, who, without any 
capacity or requitite abilities, pretend to 
teach others; and who, not knowing. 
even the principles of the {cience, and un- 
able to comprehend even the fimpleft the- 
orem in geometry, pick up here and there 
a few practical rules, and, tlrowing them 
together in a loofe diforderly manner, ar- 
rogate to themfelves the title of /ravams. 
Such men, inftead of afluming unbecéming 
airs of importance, fhould firft learn the 
moral duties of modefty and decorum. — 
Now in order to furm a true and decided 
judgment whether a propcfition is or is 
not legally and {cientifically demonftrated, 
the rnies of logic fhould be known pre- 
vioufly to commencing the ftudy of geome= 
try. The greater part of thofe who begin 
to learn the Elements, content themielves 
generally with barely knowing fome of 
the properties of the figures, withont 
troubiing 
