hot) for some time by placing it in warm water. From time to time test small portions with iodine solution as it grows clearer. Add saliva to a portion of hot starch; to a

cold portion testing as before.

Gluten

May be the gluten separates from flour as described on page 49, or better as described in "Food and Dietetics" page Bake part of it in an oven.

41.

Experiments with other proteids also described on pages 41 and 43 of "Food and Dietetics."

Experiments with yeast described on page 45 of "Household Bacteriology," Part I.

"Digestion is Synonymous with Solution"

This statement is made on page 35. To show the relation of the length of time required to make a solution, take two equal portions of any crystals, such as washing soda or alum, and pulverize one portion. Stir each in a glass of water and observe the time for each in dissolving. Note that the time required for complete solution is determined by the largest crystal.

This experiment shows how important a part of digestion chewing is and that the teeth are primarily digestive organs. Cooking Meat

See experiment on pages 50 and 51.

Mineral Matter - Gelatin

See experiments on page 53.

References: Chemistry of Cookery, by Mattieu Williams Pages 19-31. Albumen. ($1.50, postage 16c.) Chemistry of Daily Life, by Lassar-Conn. Pages

56-66. Digestion of Food. ($1.50, postage 1oc.)

(Select and send to the School a composite set of answers to Test Questions on Part I, and report on supplemental work and experiments.)

MEETING III

(Study pages 55-65)

Cleaning: Acids, Alkalies, and Salts

Strips of litmus paper may be obtained at a drug store or will be sent from the School on request. Moisten the blue paper in vinegar, lemon juice, tomato, solution of cream of tartar, etc., and then in ammonia (even the vapor will change it), in solution of washing soda, baking soda, borax, soap, and various washing powders. If the paper is washed in running water after being turned blue with ammonia, a test for acid may usually be found in milk, molasses, and sometimes butter. One piece of paper will be found to turn from blue to red and back again to blue an indefinite number of times when wet with solutions of acids and alkalies alternately.

Buy five cents' worth of hydrochloric acid and a little caustic soda at the druggist's. As caustic soda is unpleasant to handle, it is best to have the druggist dissolve it in water. Now pour a part of the acid into a saucer or glass, with a little water, and add the solution of caustic soda until the mixture begins to turn the litmus faintly blue. In an agate• ware dish, free from worn places, evaporate the solution to dryness. A whitish substance will be found, which by testing will be recognized as common salt.

From two very active chemical substances has been formed a neutral substance- salt. Not all salts, however, are neutral. Sodium carbonate (washing soda) is chemically a salt, but it is made up of a very strong alkali forming element-sodium—and a very weak acid- carbonic acid — and the alkali properties predominate. Cream of tartar is an example of an acid salt. It is acid potassium tartrate, which is a double salt, that is, tartaric acid is added to neutral potassium tartrate, the result being a substance which has acid properties. Common alum is slightly acid to litmus paper.

Soap

Soap chemically considered is a salt, made up of a fat acid and the metallic substance sodium. The fatty acid can be separated by adding any acid like vinegar to a solution of soap. If the solution is warm, it rises as a scum to the top. It can be dissolved in ammonia, forming an ammonia soap. The sodium part of the soap unites with the acid and forms a salt. If hydrochloric acid is added to a soap solution (a sufficient quantity to make the solution very slightly acid), the fatty acid removed, and the residue evaporated to dryness, common salt will be found.

If lime water be added to a solution of soap, white clots of "lime soap" will be formed which are insoluble in water, but on collecting and drying will be found to dissolve in gasoline, naphtha, or kerosene. This is why naphtha or gasoline is useful in cleaning bath tubs, bowls, etc. Quite

a good varnish can be made of aluminum soap, made from alum and white soap, dried and dissolved in gasoline. Washing Powders

It is not difficult to get some idea of the composition of the various washing powders on the market. When acid

is added to a solution, if there is effervescence, washing soda is probably present. A skum would indicate that soap formed a part of the mixture.

Hard Water

In the experiment with cabon dioxide it was shown how carbonate of lime might be dissolved by an excess of carbon dioxide gas, the bicarbonate of lime being formed, which is soluble in water. This is an example of an "unstable" chemical compound. Simply boiling drives off the excess of carbon dioxide gas, leaving the ordinary carbonate of lime which is insoluble and is deposited on the sides of the tea kettle or other vessel. This may be shown by blowing into lime water until the cloudiness which at first appears begins

to dissolve. As it is difficult to dissolve it completely, the solution may be filtered. On boiling the clear solution, the milkiness will appear again.

Hardness that is brought about by the sulphate of lime "permanent hardness"—is difficult to remedy by any household means. Washing soda helps a little, but not very much. The so-called alkali waters of the west, in addition to sulphate of lime contain sulphate of soda and other salts, so that they are beyond remedy.

Reference: Chemistry of Daily Life - The Manufacture of Soda. Page 194.

Laundry Work

MEETING IV

(Study pages 66-88)

Bluing May Yellow Clothes: On page 70 is the statement that the repeated use of ordinary bluing may stain the clothes yellow. To prove this, dip a piece of white muslin into a strong bluing solution-about a teaspoonful of liquid bluing to a cup of water-dry the cloth with a hot iron and boil it in a little strong soap solution. The color will be seen to fade. Rinse and dry with the iron. On comparing the cloth with part of the original piece, a slight yellow stain will be seen. This is oxide of iron (iron rust) and can be proved to be such by adding a drop of pure dilute hydrochloric acid and then a drop of yellow prussiate of potash (potassium ferro-cyanide), the intense blue color produced being a test for iron. The conditions in this experiment are, of course, much more severe than obtained in ordinary washing, as most of the bluing is washed out before the clothes are boiled again, but the experiment proves the possibility. As indigo costs about a dollar a pound and Prussian blue only a few cents, practically all the bluings on the market are Prussian blue.

Iron Rust Stains

Make "rusty water" by letting a few nails stand in a can of water over night or longer. Boil some white cotton cloth in a little of the water. Try the same with wool. Strain some of the water through white muslin and boil the muslin in soapy water.

Stains

One of the classes gave a demonstration before a large audience on the removal of stains as outlined in this lesson. As the only way to learn how to remove stains is to remove stains, it would be advisable to make a few, if none are at hand, and then try the experiments on them.

References: Chemistry of Daily Life-Inks. Page 178.

Laundry Work, by Juniata L. Sheppard. (50c., postage 6c.)

(Send answers to Test Questions on Part II, and report on supplemental work.)

Baking Powder

MEETING V

(Study pages 89-111)

Perform experiments suggested on pages 90 and 91.

Reference:

Lighting

Baking Powders. Bulletin No. 119, Maine Agricultural Experiment Station. (Loaned for 2c.)

(1) See Experiment page 93.

(2) Insert the small end of a clay pipe stem in the inner part of a candle flame and touch a lighted match to the other and so prove that the candle is a "gas factory." 3) With a piece of wire gauze make the experiments illustrated on page 95.

or the electric

(4) Visit the local gas plant if there is one light station-obtaining permission first from the office.