SOURCE AND AVERAGE ANALYTICAL CHARACTERISTICS OF THE PRINCIPAL DRYING OILS

Oil

Source

Per cent
of oil
content

Specific
gravity
at I5°C.

Refractive
index

Saponi-
fication
number

Acid
number

Iodine
number

Per cent of
non-saponi-
fiable matter

Candlenut | Aleurites moluccana | — | 0.925 | 1.470/40° | 193 | 2 | 164 | 0.5-1.0
Hempseed | Cannabis sativa | — | 0.927 | 1.474/40° | 191 | 0.45 | 148 | I.o8
Linseed | Linum usitafissfmutn | 35~40 | 0.932-0.941 | 1.484/15° | 190-195 | 1-8 | 170-195 | 0.5-1.0
Perilla | Perilla ocimoides | 3* | o-937 | 1.487/40° | *93 | 4.3 | 190-205 | —
Poppy-seed | Papaver somniferum | 45 | 0.924-0.926 | 1-477/15° | 190-195 | I-IO | 140-158 | 0.5
Soya bean | Glycine hispidu | 18 | 0.924-0.926 | 1.468/40° | 190-192 | o-5 | 126-135 | 0.5
Sunflower | Helianthus annuus | 5° | 0.924-0.926 | L473/25^0 | 188-193 | 6-12 | 125-140 | 0.3-0.5
Tung | Akurites cordata | 50 | 0.936-0.943 | 1.522/15° | 191-196 | O-I2 | 160-175 | 0.5-1.0
Walnut | Juglans regia | 63-65 | 0.924-0.927 | 1.480/15° | 190-197 | 2.5 | 140-150 | 0.5-1.0

w
u
t-4
§

THE DRYING CURVES OF LINSEED OIL

d

02

lO DAYS

~\s\
£O D/WS

30 OKY6

6O PAY.5

The weight increase of drying linseed oil, as a result of combination with oxygen is shown graphically. In these curves which
have been adapted from A. Eibner, Vber Fette 6/e, p. 30, table I, per cent increase in weight is plotted against drying time
in days. Curve a shows it for linseed oil, cold-pressed and prepared as a film in the dark and weighed in red light. Curve
b is for the same oil prepared and dried in diffuse daylight. I = point of initial set; 2 = tacky stage; 3 = tack-free dryness.