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through lime-water. (In these four experiments has the gas produced the same effect on lime-water?) (14.) To ascertain the composition of the gas: (a) Burn charcoal in oxygen, and test the resulting gas with lime-water; (b) burn magnesium wire in a bottle of carbon-dioxide, and note the black deposit in the resulting ash. What is this black matter? Carbon-dioxide: (15.) Lower a beaker into a jar of carbon-dioxide, draw it out again, and pour the gas into a narrow beaker, at the bottom of which is a burning taper. (16.) Balance a beaker of air on the scales, and pour in carbon-dioxide from a bottle. (17.) Invert a test-tube of the gas in a beaker of water, and allow it to remain there for a few days. (18.) Pass carbon-dioxide through a beaker of water, thus producing carbonic acid, and divide the liquid into three parts (a, b, and c). To a add a few drops of litmus-solution; then heal the solution, and notice the restoration of the blue colour. To b add a few drops of lime-water. Boil c for a few minutes, and then test with lime-water. (19.) Effect of carbonic acid on marble or limestone: Pour some distilled water on some fragments of the stone, and then add a few drops of amnion i urn-oxalate. If any lime has been dissolved, there should be a precipitate of oxalate of lime. Next place some lumps of marble in water containing carbon-dioxide iv solution, allow to stand for a short time, and then test for lime. (20.) Decomposition of carbon-dioxide by green leaves in presence of sunlight: Place watercress in a bell jar containing water previously saturated with carbon-dioxide. Invert in a plate or trough of water, and collect bubbles of gas in a closed tube passed through the cork at the top of the jar. Test the gas collected with a glowing splinter. Experiments with Water.—(l.) Put some rain-water, spring-water, and sea-water into three separate saucers, evaporate, and compare the residues. (2.) Heat some spring or sea water in a flask or retort, and allow the steam to pass through a tube into a cold vessel and condense. Compare the water thus obtained with the original liquid. Composition, of Water: —(3.) Connect a flask containing water with an iron pipe at least a foot long, in which some iron turnings or pieces of magnesium ribbon have been placed. To the other end of the iron pipe fit a glass tube passing into a trough of water. Now heat the iron tube to redness over a Bunsen burner or Primus stove, boil the water in the flask, and collect the resulting gas over water. Test this gas with a lighted taper. Examine the iron turnings, and note any change in their appearance. (Caution: Remove the end of the leading-tube from the water before'taking away the lamp from the flask.) (4.) Amalgamate a small piece of sodium with some mercury, and place the amalgam in a basin of water. Collect the gas produced in a test-tube or small bottle. Test the gas to see if it will burn. (5.) Generate hydrogen in quantity by means of zinc and hydrochloric or dilute sulphuric acid, and collect several bottles of the gas, 'taking care to first test a small quantity in a tube with a lighted match, to see that all air is expelled from the generating-bottle. (6.) Allow a jet of the gas to burn inside a cold bottle or bell jar. What do you observe on the sides of the vessel? (7.) Mix two parts of hydrogen with one of oxygen in a soda-water bottle, and two parts of hydrogen with one of nitrogen in another bottle. Apply a light to each. (8.) Pass a current of dry hydrogen through a heated glass bulb containing oxide of copper, connected with a U tube containing chloride of lime. Weigh the bulb and U tube both before and after the experiment, and notice the change in the appearance of the copper-oxide and chloride of lime. (9.) Decompose water by electricity in a voltameter, collect the gases in separate tubes, and test them. Experiments with Hydrogen.—(l.) Insert a lighted taper in a jar of hydrogen, held mouth downwards. (2.) Pour hydrogen upwards into a jar of air. Test the gas in the upper jar with a lighted taper. (3.) Suspend an inverted beaker from one arm of a balance, and pour hydrogen upwards into it. (4.) Illustrate the lightness of hydrogen by means of a small balloon, or soapbubbles filled with the gas. Experiments with Ammonia.—(l.) Heat some flour in a test-tube with an equal quantity of quicklime, and note the effect of the fumes on (a) turmeric paper, (6) litmus paper, (c) a rod dipped in hydrochloric acid. (2.) Warm gently in a flask a mixture of ammonium-chloride or sulphate and'slaked lime. Collect the gas by upward displacement, and test as in (1). Place a lighted taper in a bottle of the gas. (3.) Solubility of ammonia in water: Warm a small quantity of strong ammonia-solution in a flask till all air is expelled, fit the flask with a cork through which a nozzle passes, and invert it in a beaker containing a solution of red litmus. Composition of Ammonia :—(4.) Allow oxygen to bubble through a strong solution of ammonia in a small flask, and apply a light to the'escaping gas. Hold a cold vessel over the flame, and notice whether moisture is deposited. (5.) Fill a long test-tube with chlorine over water, and invert it in a vessel containing ammonia-solution (half normal strength). When liquid ceases to rise in the tube, test the gas above it (a) with turmeric paper, (6) with a lighted taper. (6.) Formation of ammoniasalts: Allow ammonia gas (produced by heating the solution) to pass through (a) sulphuric, (b) hydrochloric acid, diluted with water, till all the acid is neutralised. Then evaporate the liquid. (7.) Test some of the salt produced in (6) by heating with slaked lime in a test-tube. (8.) Test for ammonia: Note the result produced when a few drops of Nessler's solution are added to water containing a trace of ammonia. Apply the same test to (a) rain-water, (b) riverwater, (c) drain-water. (9.) Water a cabbage-plant with a solution of sulphate of ammonia (1 oz. to a gallon of water), applying the solution twice a week, and watch the effect on the foliage Experiments with Starch and Sugar.— Test for Starch .-—(1.) Prepare a solution of iodine in potassium-iodide by adding a few grains of iodine to a strong solution of potassium-iodide and allowing to stand till all the iodine is dissolved. Then add water till the fluid is of a dark-sherry colour Wet a little starch so as to make a very thin cream, add boiling water, and boil m a testtube for a few seconds. When cold add a drop of iodine-solution. A deep-blue colour will indicate the presence of starch. (2.) Starch in flour: Prepare some very thin paste with flour, and test for starch by adding a few drops of iodine-solution. (3.) Starch in bean-seed and potato-tuber : Scrape a portion of a softened bean -cotyledon or a potato-tuber into a basin, and test with the lodme-solu-tion Test for Sugar '—(4.) Prepare Fehlintr's solution in the following manner : Dissolve 35 grams of copper-sulphate in 500 c.c. of distilled water, and label " Solution A." Then dissolve 160 grams

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