592 
TShe RURAL. NEW-YORKER 
Simple Science 
By Dr. F. D. Crane 
Tannic Acid; Dyeing Fur 
I would like full directions for making 
tannic acid, U. S. P., and for dyeing 
white fur black and brown. F. E. n. 
Cranford, N. J. 
The people who make tannic acid of 
U. S. P. grade do not publish their exact 
methods, since, as in the case of many 
organic chemicals, results depend on 
methods of work which have been de¬ 
veloped at considerable expense. In gen¬ 
eral the method is to extract the best 
quality nut galls with water and then 
extract this water with a solvent which 
does not mix with it, such as ether, and 
then evaporate the extracted water, 
usually at a low temperature and in more 
or less complete absence of air. 
Investigation shows a number of fur 
dyeing formulas, but none seems to be 
adapted to general use. If you will say 
just what kind of fur and its condition, 
we will try to help you. 
dose of phosphate of lime and soda or a 
small dose of Rochelle salt. We believe 
both to be harmle.ss in the quantity which 
would be taken by any normal person. 
Phosphate baking powder is cheaper to 
make if you can get the ingredient-s, but 
they are not for sale everywhere. Twenty 
parts, by weight, of acid sodium phos¬ 
phate and 20 parts, by weight, of acid cal¬ 
cium pho.sphate are well mixed with 18 
parts, by weight, of starch. Twenty-five 
parts, by weight, of bicarbonatt of soda 
are mixed with 18 parts of starch. Then 
the two mixtures are well mixed. This is 
the formula as printed; the .starch may 
well be increased; the powder will be a 
little weaker, but will keep better. Any 
flour will do as well as starch; its pur¬ 
pose is merely to keep the dogs and cats 
apart, so to speak. Wheat flour has 
“gluten” in it, a gummy stuff: that helps 
keep in the gas, and other flours lack 
this, so moi’e gas is needed to get the 
Cleaning Crocks 
ITow can I thoroughly clean crocks 
used for eggs in water-glass? F. w. 
Michigan. 
Much depends on the sort of crock. If 
it was well glazed to begin with, washing 
in dilute, say 10 per cent, muriatic acid, 
with lots of hot water, will clean it nice¬ 
ly, and even very .strong vinegar will do 
pretty well. But if your crock had a poor 
glaze, so that the w'ater-glass solution 
soaked through it and into the soft earth¬ 
enware under the glaze, you will never 
get it really clean, although lots of hot 
T/ater and soaking will help along. 
Gas Manufacture ; Refining Kerosene 
1. How is gas made from coal; is it 
hard or soft coal, and what is left in the 
coke to make it give so much heat? 2. 
What is the process of refining kero¬ 
sene? • L. j. w. 
New York. 
1. Soft coal is put in an iron box and 
beated ; the more unstable portions of the 
coal (which is not all one thing), break 
down into simpler bodies, for the most 
part, and evaporate. Some of these do 
not condense again, and are called coal 
gas; those which do condense are the 
various coal tar.s, which are again refined, 
and ammonia and water. A large part of 
the carbon is non-volatile; this is the 
coke, which burns in air like any other 
carbon. 
2. Kerosene is treated first with sul¬ 
phuric acid and then with soda lye and 
then with water, but the exact details are 
not published for business reasons, .since 
it has cost large sums to get them to 
their present state of perfection. 
Phosphate Baking Powder ; Molasses 
1. Phosphate baking powder is adver¬ 
tised much cheaper than the tartar mix¬ 
ture you give. Is it as wholesome? So 
many of the war recipes call for more 
baking powder than our old ones that 
used wheat flour only. Why is this? 2. 
Can molasses be .substituted for .sugar 
safely ? A. I., w. 
Bradfoi'd, R. I. 
1. The controversy between the pho.s- 
phate and tartar powders has been going 
on for years, and it has to all appear¬ 
ances so large a commercial basis that 
we must decline to be drawn into it. It 
boils down to whether you prefer a small 
Thawing Drain Pipe 
What can be put in a drain pipe to 
thaw it out? What can be put in a 
spring to clean the pipe when it gets 
clogged with dirt and little weed roots? 
New York. A. n. K. 
Calcium chloride (not “chloride of 
lime”) with just a little water will run 
down under the other water to the ice 
and thaw it by chemical action. Sal am¬ 
moniac, ammonium chloride, is next best, 
and even a strong brine can be .slowly 
poured in and will run under to other 
water to the bottom. 
The spring pipe is much harder. If 
you can drain it and then plug the lower 
end, a strong solution of soda lye put in 
and' allowed to stay for .some hours may 
help .some. It will kill the roots already 
there, but they will soon grow in again. 
Of course you must flush the pipe well 
before putting it into use again. 
EeproOueed from N. Y. Eveuiug Telegram 
same rising effect. Still, in the recipes 
printed by the baking powder people in 
their advertisements it does look as if 
they wanted you to use their goods. 
2. Molasses can be substituted for 
sugar as far as you will, but you must 
allow for the water content, cutting down 
liquid elsewhere in the recipe. 
Softening Paint 
What will soften paint for felt roofing 
that has become hard in the can? 
May’s Landing, N. J. c. A. S. 
Such paints are so various in compo.si- 
tion that we can only guess the solvent, 
and if you will warm a little of the paint 
on a stick over the fire, and smell, your 
guess may be close to the truth. Turpen¬ 
tine will soften nearly all of those mix¬ 
tures, but kerosene can often be used and 
is much cheaper. If the paint softens on 
heating,* linseed oil can usually be stirred 
into the warm mixture, or a mixture of 
linseed and turpentine, or one of the 
cheap turpentine substitutes will thin it 
enough to spread. Perhaps a local paint¬ 
er can smell the paint and tell you what 
the maker used. 
Cleaning Carpets 
Wliat will take chewing gum from car¬ 
pets? Also stains, grease and any other 
.spots? H. R. M. 
Greensboro, N. C. 
White or paraffin chewing gum easily 
dissolves in kerosene, and all can be 
washed out with strong soapsuds. Chicle 
gum, the brown gum, is rather insoluble; 
the best thing we can suggest is carbon 
tetrachloride, sold in small packages un¬ 
der the name “Carbona.” It will work if 
you have patience, but is very slow. 
There is no one stain and spot remover 
for everything, and many stains are just 
as permanent as the one, which, called 
<lyes, were put on the carpets when 
made. Soft soapsuds "will help a lot, and 
soft soap is the carpet cleaning prepara¬ 
tion often sold. 
Hard Water 
Our water is very hard, containing 
lime and magnesia. We use a dishwash¬ 
ing machine and a film of lime is left on 
the dishes. How can we .soften the water? 
Where can we get “salt water soap,” or 
cocoanut oil soap? D. C. C. 
Connecticut. 
What is the best alkali to add to 
water to soften it? Our water will not 
make suds with soap. C. ii. w. 
New York. 
Is there an inexpensive way to ascer¬ 
tain ■w'hether water is hard or .soft, and 
the degree of hardne.ss? O. ii. 
New York. 
Few have any doubt as to water being 
hard after once wmshing with it, but there 
might be cases where water from a di.s- 
tance was to be tested, so the easiest 
question is last and is answered fir.st. 
For our purposes, hardness in water may 
be one, two or all three things. First, 
there may be carbonate of lime held in 
solution by a little carbonic acid, too little 
to give a marked taste. (When there is 
enough to taste we have a “mineral 
water” and usually a lot of other things 
besides lime.) Since this carbonic acid is 
easily driven off by heat, letting the lime 
go out of solution as it departs, the con¬ 
dition is known as temporary hardness, 
and, except in quartz rock countries, 
nearly all springs and wells have more or 
less of it Simple boiling is a cure, but 
as there is nearly always some permanent 
hardness also, it is rarely worth while to 
use it When lime is present in a form 
more soluble than the carbonate, usually 
the sulphate, boiling will not send it to 
an insoluble form, and when some salt, 
usually again the sulphate, of magnesia 
is present, the case is far worse. It is 
not that these little traces of lime and 
magnesia _ are going to hurt the average 
water drinker, in fact, the springs and 
wells usually described as “harder than 
Pharaoh’s heart” are frequently the best 
for miles around, the trouble begins when 
the lime and magnesia replace the soda 
and potash in soaps. 
Soaps are merely metal salts of fat 
acids, and there are as many soaps as 
there are metals and fat acids, but only 
those of the alkali metals are particularly 
soluble in neater when the commoner fat 
acids are_ used. So the best test for 
hardness is to take some rain or di.stilled 
water and one of the hard white soaps 
and make a weak soap solution, the 
exact strength does not matter. It will 
be opalescent, filter it or let stand and 
pour off. Now take some of the sus¬ 
pected water in a clear glass and drop 
in, with gentle stirring, .some of the clear 
soap solution. The depth of the cloud 
and the number of drops which continue 
to cloud will give an idea of the total 
hardness; doing the same with some of 
the same water boiled and cooled will, by 
difference, give you the temporary hard¬ 
ness. For comparison, a solution of 
known strength of calcium chloride in 
distilled water will give you a measure, 
but to do this deteimiination with any 
accuracy an optical arrangement to meas¬ 
ure the comparative cloudiness is almost 
essential, and if you want to know the 
permanent hardness in both lime and 
magnesia separately, there must be an 
analysis. But a little soap in rain water 
will give you a very fair idea of the con¬ 
dition of an unknown water. 
To get a suds, that is, a solution of soap 
in hard wmter, we can either add enough 
soap to throw out all the metals which 
make insoluble soap, and then enough 
more soap to make a suds, or we can 
pick a soap the acids of which do not 
form insoluble lime and magnesia soaps, 
or we can put the lime and magnesia out 
of solution before we add the soap. The 
finst we all do more or less; “use plenty 
of soap” has been the order to small boys 
for many years, but when the water 
really begins to be hard the pasty, in¬ 
soluble lime soaps are an annoyance and 
are liable to spot-light wash goods. 
The acids found in cocoanut oil form 
Reproduced from N. Y. Evening Telegram 
magnesia and lime soaps which are fairly 
soluble, and from this oil is made the 
soap for sailors, known as “salt water 
soap.” Cocoanut oil comes into the mar¬ 
ket in fairly large packages, and at pres¬ 
ent is worth, wholesale, about 20 cents 
a pound. One pound of caustic soda is 
dissolved in five pounds of water, and 
the solution vigorou.sly stirred into 12 
pounds of cocoanut oil which has been 
warmed enough to be entirely fluid. 
Gentle heating and stirring is continued 
for an hour*, the ve.ssel set aside for at 
least a day, and then again warmed very 
slowly and gently to a pasty state with 
stirring. As both caustic soda (soda 
lye), and cocoanut oil differ slightly, some 
“gumption” has to be used; if the_soap 
is too alkaline, a little more oil is 
stirred in, if it will not dissolve entirely 
in hot water (use rain water for this 
test if the water is very hard), it needs 
a little more caustic. This soap should 
be made in a large pot; cocoanut oil 
sometimes forms soap very quickly with 
much foaming. It is made on a large 
scale and can be bought by the box from 
ship chandlers. 
Adding something to put the lime and 
magnesia out of the w%ay is attractive 
and easy, but has the disadvantage of in¬ 
creasing the mineral element in the water 
and dishes dried by themselves might con¬ 
tinue to spot. Carbonate of soda, 
“washing soda,” is oftenest used, but 
makes the water much more caustic, 
April 20, 1918 
which is not always an advantage. Borax 
works with some water?, but never very 
w'ell. There is a compound of washing 
soda and baking soda, the “sesquicar- 
bonate of soda,” which has some of the 
advantages of washing soda and fewer 
disadvantages. At wholesale it is three 
or four cents a pound, but it seems to 
reach the general public only in small 
packages under fancy names and at 
fancy prices also. Practically the same 
effect can be reached by adding a little 
baking soda^ and a little washing soda to 
mi? ^instead of all washing soda. 
Ihe softening is done and the water is 
easier on hands and clothes. 
The lime can be really put out of the 
way only by precipitating it, and this is 
easy if you are willing to take the 
troiible. Add an ounce of ammonium 
carbonate and an ounce of ammonia 
water to a pint of w’ater, and, after solu¬ 
tion, find how many drops of this have 
to be used ^ a quart, or a gallon, of 
the water. There are few waters which 
will need more than a half teaspoonful, 
and an excess is harmless. But if you 
have magnesia also, make up a pint of 
water, a half ounce of ammonia water 
and an ounce of sodium phosphate and 
use a few drops after the other solution. 
Jhis, too, is harmless, but should be 
allowed to act for an hour or so if pos¬ 
sible. 
All the above chemicals are cheap and 
can do no harm to clothes or hands, even 
It you get too much in, and, at the dilu¬ 
tion given the ammonia will not touch 
most colors, but in case of very delicate 
colors a test should be made, bearing in 
mind that some colors are changed even 
by wetting in pure water. 
Oils for Leather 
What do you consider the best thing 
for leather boots and shoes? Where can 
puiT neat’s-foot oil and mutton tallow be 
obtained? What should be put on the 
Los Angele.s, Cal. 
Any non-drying oil, those you mention 
are as good as any, will help to preserve 
leather, and you can try out enough tal¬ 
low from a little sheep fat from the local 
butcher to last you for a year. Try out 
the sheep fat, too, if there is no repu¬ 
table oil or harness house to sell you 
neat’s-foot oil. You cannot polish a proper¬ 
ly oiled shoe, yet if you melt a little 
rosin with the oil a fair poli.sh will come 
after TOiisiderable brushing. Lamp black 
will give color. The prepared polishes 
are often made with .sulphuric acid, which 
w'ill kill the leather. The same oils may 
be used on the .sole.s, and varnish might 
help if applied when they were dry, but 
they will wear out, for that is what they 
are there for. 
Ill-flavored Water-glass Eggs 
Has anyone else had trouble with 
water-glass eggs the la.st two years? We 
have used the same formula as before, 
and last season I personally put in all the 
eggs, but they have an odd taste, not 
spoiled, but peculiar. m, k. 
Saco, Me. 
This is the first complaint to come in. 
Water glass may not be always the same, 
nor always quite pure; it is so cheap that 
no great care can be taken in making it. 
Next time take a little of the water glass 
in a tumbler, add water, and slowly stir 
in, with a clean stick, a strong water so¬ 
lution of either tartaric acid or cream of 
tartar till a bit of litmus paper no longer 
turns blue. Never mind about hitting 
the exact neutral point, the idea is to 
kill the excess of soda, so that you can 
safely taste it. The silica will go out as 
a thick paste, so you will have to stir 
well. Now you can taste and smell the 
stuff, and any queer taste or smell that 
might be present will be evident to the 
senses. Now add more of the acid solu¬ 
tion, and taste again, a sulphur smell 
may develop. If the water glass is taste¬ 
less and odorless when neutral and slight¬ 
ly acid, it cannot give a taste to the eggs, 
but if a taste or smell ai)pcar8 it is 
impure. 
Homemade Paint Brushes 
I have a lot of hair which I would like 
to make into paint brushes. Do they use 
glue? J. F. w. 
Glen Rock, N. J. 
We cannot encourage you to go into 
this unless you are willing to go some¬ 
where and learn the trade. Paint brushes 
are made in several ways, sometimes glue, 
but. of late, various cements are used to 
hold the materials together, and consid¬ 
erable machinery is required. But the 
knowledge of the art is the main thing; 
we cannot give you that on paper. 
Flavor of Frozen Potatoes 
What gives the sweet and bitter taste 
and discoloration to frozen potatoes? 
Mt. Tremper, N. Y. w. G. ir. 
The sweet taste is produced by the 
freezing of the tissues; it is harmless. 
The discoloration and the bitter taste are 
due to the decay of the frozen cells. 
They show' that the potatoes are no 
longer fit for food, although, if very well 
boiled, they might be fed to animals if 
the decay has just begun. But the boil¬ 
ing must be very well done, and there is 
some risk at best. 
