330 MEMOIR OF GEORGE WILSON. CHAP. VIII. 



IV. We must make them change into vapours or airs, or 



" gases," geist, gliaist, ghost, spirit. 



a. Coal heated in iron bottle (retort). 



b. Oil placed in vessel with wick. 



c. Candle with wick but no vessel. 

 V. Use of wick to draw up melted wax. 



a. Illustrations of capillary action. 



Sugar. 

 VI. a. Long time candle takes to light. 



b. Longer even than lamp. 

 VII. Tallow or wax melted and turned into gas. A candle a 



little oil manufactory, and also a little gas-work. 

 VIII. Thus lamp-light, candle-light, and oil or coal-gas light, 

 and wood and coal-flame, all essentially the same all 

 gas-lights ; ONLY coal and wood continue to yield heat, 

 long after they cease to give flame. 



I. a. Proof that these vapours or gases contain n. 



b. Proof that they contain c : smoke : cl. and C 4 H 4 . 

 II. This one half of subject : need of air. 

 III. AIT feeds flame or supports it. 



Candle in air. 

 IV. Composition of Air. 



a. ^(hpure, vital, or oxygen. Stick and Candle. 



b. itths non vital, nitrogen. 



V. Burning, a uniting of c H with o. 

 Illustration from blue and yellow - green. 



VI. What they produce when combined ? 



a. Water. Oxyhydrogen blowpipe heat. 



b. Carbonic acid. Cause of light : Limeball. 



c. Its flame- extinguishing, deadly properties. 



VII. Proof of God's wisdom in giving us c and H and air as 



combustibles. 



s in suffocating and $)oisonous. 

 Fe in white, hot anclfusibl<: 

 P in o acid and irrespirable. 

 VIII. HO and C0 2 gases, volatile, invisible 

 Importance of ventilation. 



