128 



CHEMISTRY. 



[Lesson XIII. 



151. T. What is carbonic acid gas ? 



P. An extremely poisonous gas. It 

 is incapable of supporting combustion, 

 and therefore differing from carbonic oxide, 

 which is a combustible that burns with a 

 pale blue flame. The former contains its 

 own volumes of oxygen, and the latter only 

 half its volume of oxygen. 



1.32. T. How is carbonic acid gas ob- 

 tained ? 



P, By decomposing a carbonate with 

 one of the strong acids, and collecting the 

 same as chlorine, only with this difference, 

 that we do not require heat, and that the 

 gas should pass through a long tube filled 

 with fragments of chloride of calcium. 

 [Experiment 34.] Take a piece of marble, 

 break it into small pieces the size of a 

 pea, and put ten drachms of it into a 

 bottle like that used for generating hy- 

 drogen (Fig. 33), then add six drachms 

 of distilled hydrochloric acid (equal parts 

 of water and acid) by means of the tube- 

 funnel. [Experiment 35.] Repeat the 

 above experiment, only substitute car- 

 bonate of ammonia instead of marble. 



153. T. Illustrate its properties by 

 experiments. 



P. [Experiment 36.] Here is ajar of 

 carbonic acid. I will 

 plunge a lighted taper 

 into it, holding the jar 

 mouth upwards. [Does 

 so.] You see that the 

 flame is extinguished. 

 [Experiment 37."] Here is a 

 jar with some lime-water in it 

 (A). You see that I pour the 

 carbonic acid from the other jar 

 (n) like you would water (see 

 Fig. 36). [Does so.] Observe, 

 the lime-water is milky, because 

 an insoluble carbonate of lime 

 fiy- so. has been formed. [Experi- 

 ment 38.] I will now pour carbonic acid 



upon the flame of the spirit-lamp from the 

 jar in my hand. [Does so.] You sec it 

 has extinguished it. 



154. T. What is SULPHUR? 



P. A simple elementary body, often 

 found in a free state. It is too well known 

 to require much description. In its 

 chemical relations it bears great 

 blanceto oxygen. It is insoluble in water 

 and alcohol, but soluble in bisulphuret of 

 carbon, the fat oils, and oil of turpentine. 

 It has no taste, nor smell, and is fusible. 



15J. T. What is PHOSPHORUS? 



P. An elementary body, closely allied 

 to sulphur, nearly colourless, and resem- 

 bles partially bleached wax. It is in- 

 soluble in water, but dissolves iii oils, 

 alcohol, and sulphuret of carbon. 



156. r. How is it prepared? 



P. By decomposing the phosphate of 

 lime in bones, by means of sulphuric acid, 

 and then causing it to undergo a long pro- 

 cess, which I will not describe, as it is not 

 sufficiently useful. 



157. r. What is BORON? 



P. An elementary substance procured 

 from borax, but as I have never seen it, 

 (and I believe very few persons have,) it is 

 as well to pass it over. 



158. T. What is ALUMINUM ? 



P. A metal, and therefore I shall defer 

 its description until another opportunity 

 occurs of examining all the important 

 metals. 



[The pupil should consult Cat. XI.] 



GENERAL QUESTIONS ON LESSON XIU. 



1. What is the purest kind of carbon ? 



2. Describe and illustrate the properties 

 of carbon. 



3. What is carbonic acid gas ? 11 w is 

 it obtained, and what are its properties? 



4. \Vhat is sulphur, phosphorus, and 

 boron ? 



. EOL1XGTOX, 1'IU.NTEH, GCbV.tLL blKKKT. 



