we usually say during a storm that the elements are raging; or, "As yet amid this elemental war That scatters desolation from afar, Nor toil, nor hazard, nor distress appear, -Falconer's Shipwreck. Before we consider the properties of some of the elements, it is necessary to state that no natural or artificial operations cause their destruction. Chemistry enables us, it is true, to decompose compounds presented to us by nature, and from their compound parts to form new combinations. This we can repeat at pleasure, but the elementary bodies which we have thus sported with remain uninjured. This is one of the most certain facts with which man is acquainted. QUESTIONS. 105. What is an element? 106. Were the ancients correct in calling fire, air, earth, and water elements of nature ? 107. How many elements are we acquainted with ? 108. Are the elements ever destroyed during natural or artificial operations? LIST OF ELEMENTS. Those marked (*) will be particularly noticed in the following 1. *Oxygen. pages: 29. *Copper. 30. *Iron. 2. *Hydrogen. 4. Chlorine. 9. *Bromine. 10. Fluorine. 11. Selenium. 15. *Magnesium. 16. Yttrium. 17. Zirconium. 31. *Lead. 32. *Tin. 37. *Manganese. 40. This is one of the most important and universal agents of nature. In an uncombined or free state it is a gas this term is applied to those bodies that do not become solid or liquid at the ordinary temperature of our atmosphere. Oxygen forms about a fifth part of our atmosphere, eight parts in every nine of water, an immense portion of our solid globe, and enters into the composition of every animal and vegetable. Taking this view of the case, there is no mind that can investigate this subject without feelings of peculiar interest. The term oxygen is derived from the Greek (oğus, acid, and yevvaw, to create), as it was supposed by Lavoisier that it was the sole cause of the formation of acids: subsequent discoveries have proved that this opinion was false-the term, however, is still retained. It was discovered by Dr. Priestley in 1774. 41. It can be obtained from various sources, from which we select the following: Experiment 18.-Put one or two ounces of black oxide of manganese, a compound of oxygen and manganese, into a small glass or earthenware retort, (fig. 3,) with about an equal weight of sulphuric acid FIG. 9. (vitriol). On applying the heat of a lamp, the sulphuric acid will seize the metal manganese, and liberate the greater portion of the oxygen, which can be collected in inverted glass vessels placed on the shelf of the pneumatic trough-(so termed from TVEVμa, air or gas, as it is only used for collecting gases.) A little practice will enable a young person to use it.-(Vide fig. 9.) The wood-cut represents a tin pneumatic trough of Griffin convenient dimensions are, thirteen inches long, seven wide, and four deep. The shelf B is one inch wide, and C three inches. At the end there is a pipe, F, half an inch from the top, that carries off the water as it flows from the various jars during the operation of filling them with gas the sliding vessel E receives this discharged water. The shelf D, perforated in the centre, moves along B and - C; the dotted lines represent a tin vessel soldered beneath, to prevent any gas from being lost as it passes from the retort, the beak of which is placed under it. To collect gas by this apparatus, a glass jar is filled with water, and inverted, as in fig. 5, upon the moveable shelf D (fig. 9.) As the gas enters the water is displaced, and flows through F into E. The jars, when filled with gas, may be left on the fixed shelf C, or removed with their mouths in trays containing water, as in fig. 5. FIG. 50 to The earthenware chemical apparatus, bido constructed by Mr. Griffin of Glasgow, aolfoodT is admirably adapted for beginners int the expense is very trifling. Then safety-tube, fig. 4, made of glass, should be attached to the retort--its principal use is, to prevent the ex-o ternal atmosphere pressing on the water in the basin or pneumatic trough from forcing a portion of cold water into the heated retort when a vacuum would be formed by the removal of the lamp (examine carefully exper. 15.) The safety-tube is about sixteen inches long, bent as in the figure--the dotted lines represent water. When a vacuum is formed, the air rushes through the tube into the retort, forcing a passage through this small portion of water. Experiment 19.-We can procure a considerable quantity of oxygen by using the black oxide of manganese alone-in this case a greater heat must be employed. Instead of a glass retort, a cast-iron bottle is employed with a small iron tube ground into it the other extremity dips into the pneumatic trough. As the heat of a lamp is insufficient, the vessel must be placed in the fire. An old gunbarrel, having the touch-hole closed, is an excellent D |