9 2 SCIENTIFIC AGRICULTURE. 



wide-mouthed bottle, the mouth dipping under the surface 

 of the water. After the phosphorus has ceased burning, 

 the water will absorb the white fumes of the phosphorus 

 oxide, and rise in the bottle. The gas which remains is 

 nearly pure nitrogen. A lighted splinter or candle if brought 

 into the nitrogen will be extinguished. 



(10.) Rub together in a mortar a little ammonium chlo- 

 ride (sal-ammoniac) and quicklime. Ammonia will be given 

 off, which can be detected by its pungent odor. Bring a 

 piece of red litmus-paper in contact with this gas, and it 

 will turn blue immediately. 



(n.) Place a few bits of copper in a wineglass, and 

 pour over them a little nitric acid. Red fumes of nitrogen 

 tetroxide will be formed. The blue liquid that is left con- 

 tains copper nitrate. 



(12.) Dip a piece of paper in spirits of turpentine and 

 light it. The black smoke consists of finely divided carbon. 

 Hold a piece of window-glass over the flame of a candle, 

 pushing it down upon the flame, and it will soon be coated 

 with carbon. 



(13.) Place some small pieces of marble or limestone in 

 a deep wineglass or bottle, and pour over them a little 

 hydrochloric acid. The brisk effervescence that takes place 

 is caused by the escape of carbon dioxide. A burning 

 splinter or candle will be extinguished if lowered into the 

 bottle. 



(14.) Bum a small piece of sulphur, and hold a red rose 

 or other flower over the fumes. The flower will be bleached. 

 A similar effect may be produced with a sulphur-match. 



(15.) Place a splinter of wood in strong sulphuric acid, 

 and it will turn black. The acid does not act on the car- 

 bon of the wood. Pour a little of the strong acid into a 

 wineglass of water, and the water will become very hot, 



