298 
Wea TORE 
[Fuly 29, 1886 
and 53°3 parts of oxygen. It is neutralised by alkalies like sul- 
phuric acid. Iron put into it is slowly dissolved, hydrogen being 
given off. Oxide of lead dissolves in it, forming a salt, and if 
the clear solution be evaporated a white crystalline body called 
‘sugar of lead’? is formed, which is lead acetate. The vinegar 
smell belongs only to the acid, not to the salts. Sodium acetate 
has no smell ; add toit sulphuric acid and warm, when the smell 
shows the acid has been liberated and that it is volatile. 
Experiments.—Show that vinegar has the properties of an 
acid, and that a salt is formed on neutralising it. Show a 
specimen of the commercial acetic acid, and point out its colour- 
less appearance and strong smell and acid reaction. Show that 
iron is acted on and dissolved by acetic acid. Make sugar of 
lead by dissolving lead oxide in acetic acid, and crystallise out 
the salt. Point out disappearance of the pungent odour of the 
acid on neutralisation by potash or soda. Demonstrate the 
liberation of the acid as indicated by the odour on addition of 
sulphuric acid to sodium acetate, and show that it can be 
separated from the liquid by distillation. 
TARTARIC AcID.—Occurs in many fruits; especially in 
““c 
grapes. Is obtained from ‘‘argol,” an impure potassium salt of 
tartaric acid, deposited when grape juice ferments. Tartaric 
acid is a crystalline solid, and dissolves easily in water. Has no 
smell. Is composed of carbon, hydrogen, and oxygen, 7.e., the 
same elements as are in acetic acid but in different proportions, 
viz. : 32°0 parts of carbon, 40 parts of hydrogen, and 640 parts 
of oxygen. Its action on sodium carbonate. Effervescing 
draughts ; seidlitz powders. Tartrates. 
Experiments.— Specimen of argol and of crystals of tartaric 
acid. Show solubility of the solid acid in water, and that the 
solution has acid properties and is without odour. Demonstrate 
the presence of carbon in the acid by ignition. 
Far AND OILs.—Are neutral bodies made up of an acid and 
a base, the base in all cases is glycerine, the acid varies in 
different oils and fats. They are all insoluble in water. Oils 
are liquid ; fats are solid. Many of the oils are obtained from 
vegetables, either from the seed or fruit. Most of the fats are 
from animals. Melting of tallow (fat of the ox, sheep, &c.) 
put in boiling water. Its non-solution in water. Its lightness 
as compared with water. If a solution of caustic potash be 
added, and the solution of the liquid boiled, the fat disappears 
and the liquid becomes slightly milky, and nearly the whole 
dissolves. Combination of the potash with the acid (stearic) of 
the tallow and formation of potassium stearate. Previously the 
stearic acid was combined with glycerine. To the solution of 
potassium stearate hydrochloric acid is added. The potash is 
again separated from the stearic acid, and the stearic acid, 
as it cannot dissolve in water, separates out. Stearic acid dis- 
solves in alcohol and in ether and separates out in crystals. 
Used in making candles, and is better than tal'ow because it 
melts at a higher temperature. Tallow distilled with steam of 
temperature 609° F. (high pressure steam). separates into stearic 
acid and glycerine, and when cold these bodies remain separate. 
All oils and fats are decomposed by potash in the same way as 
tallow. 
Experimen’s.—Tie beef or mutton fat up in muslin bag, and 
melt to separate the fat from membranous matter Show that 
fat is insoluble in water, that it floats on water, and melts at a 
temperature below boiling water. Show that oil has very similar 
properties to melted fat. Boil oil or fat with caustic potash. 
Prepare a solution of potassium stearate, and precipitate stearic 
acid from it by the addition of hydrochloric acid. Show the 
solubility of the acid in alcohol and ether, and the insolubility 
of the lime salt of stearic acid. 
GLYCERINE.—A thick colourless liquid with a sweet taste. 
Dissolves readily in water. When quite pure becomes solid 
at a low temperature. If heated alone it is destroyed, but if 
heated with water in a retort it distils over with the steam. 
Heated with acids it combines with them, and bodies similar to 
fats are formed. 
Expertment.—Specimen of glycerine. 
bility in water and its sweet taste. 
Soapr.—By boiling fat with caustic soda sodium stearate is 
formed. On adding salt to the liquid the sodium stearate, which 
is soap, separates out and solidifies on the surface of the liquid. 
Soft soap is potassium stearate. Action of soap in washing. 
Action of soap on hard and on soft waters. 
Experiment.—Shake distilled water up in bottle with soap. 
Show action of solution of salts and acids on the solution. Add 
soap solution to distilled water, also to common water, and 
Demonstrate its solu- 
J 
explain the difference of action. Show the presence of stearic 
acid in soap by adding hydrochloric acid to a solution of soap. 
SuGAR.—Exists in many plants. Is obtained from the sugar- 
cane ; also from beetroot. The juice of these plants yields the 
sugar. When pure it is white, crystalline, sweet, and very 
soluble in water. Sugar candy. If heated with very little water 
to 365° F., on cooling it is no longer crystalline and is ‘* barley 
sugar.” Does not combine with acids, but even a very little 
acid boiled for a long time with a solution of sugar changes it 
to another kind of sugar. Composition of cane sugar. The 
several different kinds of sugar, e.g., the solid part of honey is 
a sugar which differs from the sugar in the sugar-cane ; the same 
found in all sweet fruits and is called grape-sugar. Grape-sugar 
not so sweet nor so soluble as cane-sugar. 
Lxperiment.—Specimens of ordinary white and brown sugar ; 
also sugar candy and barley sugar. Show its great solubility in 
water ; also that its solution is neutral. Heat it and point out 
the peculiar odour it gives oat, and that on further continuing 
the heat it leaves a residue of carbon. Wash honey with spirit, 
and show the residue is sugar, but that it is not sweet as ordinary 
sugar, and not so soluble. 
STARCH.—A neutral substance, composed of carbon, hydrogen, 
and oxygen. Composition. Peculiar structure ; not crystalline. 
Is found in all parts of a plant. Is obtained from wheat, rice, 
potatoes, arrowroot, &c. Starch in its ordinary condition in- 
soluble in water. When starch powder is boiled with water, the 
membrane of starch cells bursts, and the starch is partially dis- 
solved. Strong solutions form a jelly when cold. Used for 
stiffening linen. Starch recognised by its forming a blue com- 
pound with iodine. Undergoes no change in the air at ordinary 
temperatures ; if heated to about 300° F. it becomes slightly dis-~ 
coloured and is changed into a soluble body, known as British 
gum (dextrin). If small amount of nitric or hydrochloric acid 
be added to the starch this change is more rapid. Extract of 
malt also changes starch into soluble compounds. Starch as a 
food. 
Experiment.—Specimen (of starch), point out its peculiar 
structure and absence of crystalline form, Demonstrate that it 
does not dissolve in cold water, but on boiling some does dis- 
solve. Show that starch both solid and in solution gives a blue 
colour when iodine is added to it. Moisten starch with very 
dilute hydrochloric acid, and heat to convert it into a gum, 
which is thus soluble in water. 
GLUTEN.—TIf flour is tied up in a calico bag and well kneaded 
in a basin of water, the water becomes milky, and on standing 
starch sinks to the bottom. All the starch in the flour can thus 
be removed, and then a sticky substance remains in the bag 
called gluten. About 70 per cent. of flour is starch and 10 per 
cent. is gluten. Gluten contains nitrogen, starch does not. These 
bodies represent two most important constituents of food. 
The gluten exposed to the air soon decomposes and smells very 
disagreeably (putrifies). 
Experiment.—Tie some flour up in a piece of calico and knead 
it for some time in a vessel of water ; the starch comes through, 
and will settle to the bottom of the vessel, and can be collected 
and examined ; the gluten remains in the bag. 
Spirit.—Alcohol, spirits of wine. A colourless, light liquid. — 
Neutral to test papers. Has pleasant odour, boils at 173° F. 
Burns with a flame, which gives very little light, without leaving 
any black residue of carbon. A large number of different 
bodies dissolve in it. It is the intoxicating principle in wines 
and spirits. In beer there is 3 to 5 per cent. of alcohol. In 
light wines about 8 per cent. In spirits 60 to 75 per cent. The 
different flavours of wines and spirits depend on very small 
quantities of other bodies present. Alcohol dissolves in water, 
giving out heat. 
«Proof spirit” contains 50°76 parts of water, and 49°24 parts 
of alcohol. If more water be present the spirit will not set fire 
to gunpowder when burning. Alcohol obtained from grape 
sugar. Fermentation grape sugar converted into alcohol and 
carbon dioxide by presence of some ferment which exists in 
yeast. Cane sugar on the addition of yeast is first converted 
into grape sugar, then into alcohol and carbon dioxide. Use of 
yeast in brewing. Not neces ary for making wine, as there is 
already a ferment in expressed juice of grape. mney 
Experiment.—Show it is neutral liquid dissolving in water, 
that it burns with nearly colourless flame, and leaves no residue 
of carbon. Show that it can be made to boil at much lower 
temperature than water by placing test-tube of it in hot water. 
Distil beer and collect the alcohol and water which comes over ; 
> 
% 
