Feb. 1, 1895.] Supplement iu the " Tropical Agriculturist," 
573 
per gallon is fairly good. 
Magnesia.— Magnesia is of somewhat rare occur- 
rence in water, but in s una localities it may be met 
with in considerable" quantities. A quantity Of 
water should be evaporated in a small porcelain 
basin, over the spirit lamp to one fiftieth of its 
volume. To this taken in a test-tube, ammonium 
oxalate is added and tillered to remove any lime. 
The resulting filtrate should be trexted with a 
few drops each of the solutions of sodium phos- 
phate, ammonium chloride and ammonia solution. 
If any magnesia be present a crystalline precipi- 
tate will be observed after the liquor is allowed 
to rest for twenty-four hours. 
Iron.— -The presence of iron is indicate 1 by a 
blue precipitate on the addition of potassium fero 
cyanide. • , in iii>J 
Lead. — Place some water iu a white dish and 
stir up with a rod dipped in ammonium sulphide, 
a dark colour not disappearing on the addition of 
a few drops of hydrochloric acid will be produced. 
Copper also presents the reaction, but the 
presence of lead or copper may be distinguished 
by adding a few drops of sulphuric acid and 
filtering the water before it is tested. If a slight 
cloudiness is observed on the addition of sulphuric 
acid it indicates lead, and if the solution tested 
after filtering gives the dark colour described 
above it indicates copper. 
Zinc is rarely found except as an impurity 
in connection wit h a storage cistern. A white pre- 
cipitate on the addition of sulphuretted hydrogen 
indicates its presence. 
Chlorine.— The addition of a few drops of 
nitric acid and silver nitrate produces a mere 
haze if chlorine is present to the extent of a grain 
per gallon ; four grains give a marked turbidity 
and ten grains a considerable precipitate. The 
presence of chlorine in water indicates impurities 
from dissolved mineral chlorides or urine and 
sewage. 
Suiphwic acid. — On the addition of barium 
chloride a grain and a half of sulphuric acid 
per gallon of water would give a precipitate aftera 
while, three grains would give an immediate haze. 
The presence of this impurity indicates mineral 
sulphates such as those of lime and sodium, The 
presence of the former deteriorates the quality of 
water for industrial purposes greatly. 
Phosphoric acid. — Concentrate a quantity of 
water by evaporation and the addition of molybdate 
of ammonium and nitric acid followed by a slight 
heating and allowing the solution to stand for a 
while, would give a yellow colour if phosphoric 
acid be present. The presence of this substance 
indicates animal and vegetable impurities in the 
water. 
Nitric acid. — Add a solution of brucine to the 
water to be tested, and pour strong sulphuric 
arid ; if nitric acid be present a red-coloured zone 
forms at the margin of the sulphuric acid and 
water. Instead of brucine, sulphate of iron may 
be substituted when the colour of the zone will be 
brown ; — nitric acid indicates mineral as well as 
organic impurities. 
Ammonia. — On the addition of two or three 
drops of N'essler's reagent to about one-fourth of 
n test-tube full of water, and examining the tubo 
over a white piece of paper, a yellow colour is 
seen, indicating the presence of ammonia. Small 
quantities give only a slight tint, but even then 
the water is suspicious, and may be contaminated 
with urine, sewage and other organic impurities. 
Oryanic matter is best observed by evaporating 
to dryness a quantity of water in a porcelain basin 
and heating the residue, which, it' it blackens, 
indicate the presence of organic matter. 
>Ve next come to th ' third method of testing, 
i.e., for hardness. Water is said to be hard when 
it contains dissolved matt (ft in it, but as a rule 
the term fi hard" is used to denote the preseuce 
of either carbonate of lime (chalk) or sulphate of 
lime (gypsum). The hardness due to the presence 
of chalk is removable either by boiling or by the 
addition of lime-water, and is hence known as 
" removable hardness," whereas water containing 
gypsum is known as permanently hard. 
Hardness.— There are various elaborate pro- 
cesses of determining the degrees of hardness of 
water, and these, of course, give very accurate 
results but demand care arid labour which .no on« 
but a professional chemist could bestow liar 
ordinary purposes the following method » may 
prove serviceable. Instead of the " soap test', we 
substitute " soap liniment" prepared accord u g in 
the British Pharmacopia strength, which any dr ug- 
gist would supply. The test consists iu the quan- 
tity of the soap solution necessary to form a lather 
in the water. If one drop of soap solution put in 
half an ounce of water forms a lather, we conclude 
that the water contains less than one-and-a-half 
grains of lime per gallon, and an additional drop of 
the soap solution represents an additional one- 
and-a-half grains. The number of grains repre- 
sents the degree of hardness ; for example, if half 
an ounce of water requires four drops of the 
soap solution, it indicates six degrees of hardness. 
In order to find the amount of permanent hard- 
ness, a quantity of boiled water should be treated 
iu the same way, and the result will indicate the 
permanent hardness. The difference between 
total ana] permanent hardness will give the 
degree of removable hardness. The permanent 
hardness of good water should not be be above 
3 or 4 degrees. 
W. A. D. S. 
GENERAL ITEMS. 
A Loudon physician not long ago published an 
interesting paper in the Lancet on the use of fruits 
in the relief of diseased conditions of the body. 
Under the category of laxatives, oranges, figs, 
tamarinds, prunes, mulberries, dates, nectarines 
and plums may be included. Pomegranates, 
crauberries, blackberries, raspberries, barberries, 
quinces, pears, wild cherries and medlars are 
astringent ; grapes, peaches, strawberries, 
whortleberries, prickly pears, black currants aud 
melon seeds are diuretics ; gooseberries, red aud 
white currants, pumpkins and melons are 
refrigerants and stomachic sedatives. Taken in 
the early morning an orange acts very decidedly 
as a laxative, sometimes amounting to a 
purgative, aud may generally be relied on. Figs, 
slit open, form excellent poultices for boils 
and small abscesses. Strawberries and lemons, 
locally applied, are of some service in the 
removal of tartar from teeth. Apples are cor- 
rectives, useful in nausea, and oven seasickness 
and the vomiting of pregnancy. The oil of the 
coconut has been recommended as a substitute 
