ENGLISH INDEX
585
numbers) 77 : any square is sum
of two triangular numbers 8B-4 :
8 times a triangular number
+ 1 = square, 84, ii. 516.
Ssade, Phoenician sibilant (signs
TiiTlT) became (900) 32.
‘ Stadium,’ 1 /60th of 80°, ii. 215.
Stadium of Zeno 276-7, 281-8.
Star-pentagon, or pentagram, of
Pythagoreans 161-2.
Stereographic projection (Ptolemy)
ii. 292.
Stevin, S. ii. 455.
‘ Stigma,’ name for numei’al “T,
originally C (digamma) 32.
Strabo 121, ii. 107, ii. 220.
Strato ii. 1.
Subcontrary (= harmonic) mean,
defined 85.
Subtraction in Greek notation 52,
Surds: Theodorus on, 22-3, 155-6,
203- 9, 304: Theaetetus’s general
ization 203-4, 205, 209, 304 : see
also ‘Approximations ’.
Surface-Loci 219, ii. 380-5: Euclid’s
439-40, ii. 119, ii. 425-6.
Sunja-Siddhdnta ii. 253.
Sussu = soss (Babylonian for 60) 28,
ii. 215.
Synesius of Gyrene ii. 298.
Synthesis 371-2: defined by Pappus
ii. 400.
Syracuse 8.
Table of Chords 45, ii. 259-60, ii.
283.
Tdittinya Samhitd 146.
Tannery, P. 15, 44, 87, 89,119, 132,
180, 182, 184, 188, 196 n., 232,
279, 326, 440, ii. 51, ii. 105, ii.
204- 5, ii. 215, ii. 218, ii. 253,
ii. 317, ii. 453, ii. 483, ii. 519,
ii. 538, ii. 545, 546, ii. 550, ii. 556,
ii. 561.
Teles on secondary education 21.
Teos inscription 32, 34.
Tetrads of Apollonius 40.
Tetrahedron: construction 416, ii.
368 ? volume of, ii. 335.
Thabit b. Qurra : translator of Eu
clid 362, 363: of Archimedes’s
Liber assumptorum ii. 22: of
Apollonius’s Conics Y-YII ii. 127:
of Menelaus’s Elements of Geo
metry ii. 260:, of Ptolemy ii.
274-5.
Thales 2, 4, 67 : one of Seven Wise
Men 128, 142: introduced geo
metry into Greece 128: geometri
cal theorems attributed to, 130-
7: measurement of height of
pyramid 129-30, and of distance
of ship from shore 131-3: defini
tion of number 69 : astronomy
137-9, ii. 244: predicted solar
eclipse 137-8.
Theaetetus 2, 119, 170: on surds
22-3,155, 203-4, 205, 209, 304:
investigated regular solids 159,
162, 212,217: on irrationals 209-
12, 216-17.
Themistius 221, 223, 224.
Theodorus of Gyrene: taught mathe
matics 22-3: on surds 22-3, 155—
6, 203-9, 304.
Theodosius ii. 245-6: SphaericaZAd-
50, ii. 246-52: other works ii.
246; no trigonometry in, ii. 250.
Theologumena arithmetices 96, 97,
318.
Theon of Alexandria : examples of
multiplication and division 58,
59 -60 : extraction of square root
61-3: edition of Euclid’s Elemen ts
360-1, ii. 527-8: of Optics 441,
ii. 528 : Catoptrica ib.: commen
tary on Syntaxis 58, 60, ii. 274,
ii. 526-7.
Theon of Smyrna 12, 72, 73, 74, 75,
76, 79, 83, 87, ii. 515: treatise
of, ii. 238-44 : on ‘ side- ’ and
‘diameter-numbers’ 91-3, 112:
forms of numbers which cannot
be squares 112-13.
Theophrastus 158, 163: on Plato’s
view of the earth 315.
Theudius 320-1.
Theuth, Egyptian god, reputed in
ventor of mathematics 121.
Thevenot, M. ii. 308.
Thrasyllus 97, 176, 177, ii. 241, ii.
243.
Thucydides ii. 207.
Thymaridas : definition of unit 69:
‘ rectilinear ’ = prime numbers
72 : firavdryia, a system of simple
equations solved 94.
Timaeus of Loeri 86.
Tittel ii. 300, 301, 304.
Tore (or anchor-ring): use by Ar
chytas 219, 247-9: sections of
(Perseus), ii. 203-6: volume of
