ELEMENTS. By the Elements are known all those substances which analysis has failed to further reduce or sub-divide. All the material universe around us is composed of these materials in various forms of association. Carbon, Oxygen, Hydrogen and Nitrogen prevail in the animal and vegetable kingdoms, whilst Aluminium, Calcium, Carbon, Chlorine, Hydrogen, Iron, Oxygen, Silicon, Sodium, and Sulphur make up the greater part of the mineral kingdom. Many of the Elements exist in very small quantities; several are rarer than gold. The following table gives the chief Elements, together with (1) the "Symbols" by which they are denoted in Chemistry; (2) their Atomic weights or smallest combined proportions, taking Hydrogen as 1; (3) their Atomicity, or the multiples of their atomic weights by which they may combine; (4) their Specific Gravity, taking Water as 1. The specific gravity of any substance (water being taken=1,000) gives the weight in ounces of a cubic foot approximately. Thus: 1 cubic foot of water weighs approximately 1,000 ounces=62.5 lbs. 1 cubic foot of lead (spec. grav. 11360) weighs approximately 11,360 Ounces=710 lbs. To find the area of a circle: square the diameter and multiply by .7854. To find the contents of a sphere: Cube the diameter and multiply by .5236. To find the contents of a cylinder=c: (1) The weight of 27.7015 cubic inches of pure water at maximum density, of 39°.2 F. The pound Troy contains 7,560 grains, and is divided into 12 ounces of 480 grains each. The grain Troy and the grain Avoirdupois are the same. (2) The ton of 2,000 pounds is the "metric" or short ton. The following are minimum weights of the respective materials according to the U. S. laws and usages: (3) The weight per bushel of salt varies widely in different States with the quality of salt, and ranges from 50 to 80 pounds. METHOD FOR INTER-CONVERTING THE THREE THERMOMETER SCALES. °C. to °R., multiply by 4 and divide by 5. R. to °C., multiply by 5 and divide by 4. R. to °F., multiply by 9 and divide by 4: then add 32. °C. to F., multiply by 1.8: then add 32. °F. to °C., first subtract 32: then divide by 1.8. °F. to °R., first subtract 32: then multiply by 4 and divide by 9. TO FIND THE CAPACITY OF ROUND VATS IN BARRELS OF 31 GALLONS. Diam. in feet. 5 6 7 8 9 ΙΟ II 12 13 14 15 16 17 18 19 20 23.69 34.11 46.43 60.65 76.76 94.76 114.66 136.46 160.15 185.74 213.21 242.59 273.87 307.03 342.10 379.05 |