The definitions of the Jew terms which follow here are added to the general data
on fainting materials in order to clarify somewhat further technical words used in
the foregoing text. Most of those not defined here will be readily located in a dictionary.
The definitions given may not completely explain the meanings of all the terms y but
it is hoped that they may be of some help. They are taken^ with a little modification^
f?om standard reference works in the various branches of science.

A, a symbol for Angstrom unit which is a
measure of length, usually of the wave-
length of light, i A = io"7 millimeters or
io~10 meter or 0.000,000,0001 meter;
io A = I millimicron (rn/z).

A.S.T.M., American Society for Testing
Materials.

Acicular, needle-like or slender in shape.

Acid, a chemical compound which contains
hydrogen as a positive radical and in solu-
tion gives hydrogen ions (H+); it neu-
tralizes bases, yielding a salt and water;
e.g., HC1 (hydrochloric acid), H2S04 (sul-
phuric acid), and CH3COOH (acetic acid).

Acid Number or Value, a measure for free
fatty acid in animal and vegetable fats;
expressed as the number of milligrams of
potassium hydroxide required to neutralize
the free fatty acids in one gram of the fat.

Acid Salt, a compound derived from an acid
and a base in which only part of the hydro-
gen of the acid is replaced by a basic
radical; e.%., an acid carbonate, NaHCOs
(sodium bicarbonate), or an acid phosphate,
NaHgP04 (sodium dihydrogen phosphate).

Aliphatic, belonging to or derived from fat;
belonging to that group of organic com-
pounds having an open- or straight-chain
structure as opposed to a ring or cyclic
structure (see Aromatic). The aliphatic
compounds include not only the fatty acids
and derivatives of the paraffin hydrocarbons
but also unsaturated compounds of the
ethylene and acetylene series; e,g.9 butane,
CH,CHtCH«CH,; ethylene, H2C - CH2;
and acetylene, HC s CH«

Alkali, essentially the hydroxides of the
metals, lithium, sodium, potassium, ru-
bidium, and caesium, but also the car-
bonates of these metals and of ammonia;
*.£., NaOH (sodium hydroxide) and KaCOs /
(potassium carbonate).

Alum, ordinarily the double sulphate of alumi-
num and potassium, KaSCVAlatSO^s*
C^HaO; also the generic name for other
double sulphates of monovalent and triva-
lent metals which are isomorphous in
crystalline form and contain 24 molecules

of water of crystallization, like ammonium
alum and chrome alum.

Amorphous, a term applied to materials
which apparently do not have crystalline
form; unorganized; without definite form;
structureless.

Amphoteric, said of a substance that has both
acid and basic properties; e.g., aluminum
hydroxide, A1(OH)3.

Anhydrous, said of a compound which is with-
out or has lost water, in particular, its water
of crystallization.

Anisotropic, having different physical proper-
ties in different directions, like crystals; as
regards the transmission of light, a sub-
stance which is doubly refracting (see
Isotropic).

Aqueous, containing water; watery; Aqueous
Solution, one in which water is the solvent.

Aromatic, belonging to or derived from that
series of organic compounds, many of which
are odorous, having a closed-chain or ring
structure of the benzene type (see Benzene)
as opposed to the aliphatic (see Aliphatic)
and alicyclic or saturated ring compounds;
**•»

OH

4

HC CH

V

H

phenol

O

H I) OH

HcAA/VoH
Hi 4 4 i-H

V V V

HUH

alizarin

3*5