Page:The American Cyclopædia (1879) Volume II.djvu/436

 16 BEAM BEAN article the term " safe load " will mean the load corresponding to that strain. The safe load will be less than one third of the ultimate or breaking strength of the beam, thus allowing a sufficient margin of strength to insure safety. The deflection of floor beams should not ex- ceed ^ of an inch for each foot of span. If the depth of the beam is not less than jL of the span, the deflection will be within that limit for the safe load. For spans for which a greater depth than 15 inches is not required, solid-rolled beams are ordinarily used, and for greater spans riveted beams. The following table gives the dimensions, weights per yard, and coefficients to determine the safe loads for rolled wrought-iron beams of the sizes most used in this country : DIMENSIONS OP BEAM 1 6 - 6 1 IN INCHES. & - a JJ! . ^ *

.- if '5 'C u s 1 1 1- I ' gf i| 1* JJ

13 15 0-6 6-75 200 74SOOO 12 tt. 882 15 0-5 5 160 ,V.l. urn 11 705 12 0-6 5-5 170 511,000 10 885 12 0-47 4-8 125 877,000 10 645 10 0-47 5 185 860.000 11 608 10 0-88 4'5 105 286,000 11 555 9 0-57 4-5 125 268,000 8 535 9 0-88 4 85 IMMiOO ' 8 485 9 0-8 8-5 70 152,000 8 829 8 0-88 4-5 80 168,000 9 566 8 0-8 4 65 185,000 8 428 7 0-33 8-5 60 102,000 6 817 6 08 8-5 50 76,800 6 824 6 0-25 8 40 (i-'.finn 6 289 5 0-81 8 40 49,100 5 261 5 0-25 2-75 80 88,700 4 218 4 0-81 i 8 87 80,800 4 268 4 0-25 2-75 80 I1II.1IIO 4 215 The safe load, uniformly distributed over the span, when the beam is supported at both ends, and lateral deflection is presented by the filling between the beams, will be found, in pounds, by dividing the coefficient given in the table by the span estimated in feet. If the span be less than that given in the column headed "Limitation of coefficient," the load should nevertheless not exceed the safe load for that span, in order that the shearing strain upon the stem shall not exceed the safe limit. The deflection at the middle of the span, for the safe distributed load as given by the above rule, will he found by dividing the square of the span, estimated in feet, by 70 times the depth of the beam, estimated in inches ; and for any less load, it will be proportionally less. If the beam is free to deflect laterally, the coefficient given in the table must be modified, to allow for the increased strain brought upon the beam, as follows: multiply the coefficient by the number given in the column headed " Correction for lateral resistance," and divide the product by the sum of that number and the square of the span estimated in feet. The strength of various forms and dimensions of riveted beams may be determined by the or- dinary formulas for the strength of materials. BEAN, the seed of leguminous plants of three genera, ftiba, pJiaseoliu, and dolic/ios, of which the fat/a vulyaris furnishes the different varie- ties of the common bean cultivated for food throughout the world. It originated in the East, is said to be still found wild in Persia, and has been known and cultivated in all ages. The French kidney bean (haricot) is tlie seed of the phaseolus vulgaru ; and in India and South America species of dolicTios are raised, such as the sword bean of India (D. ensiformis) and the Lima bean (the latter extensively cultivated in the United States), and furnish an important item of food. The common bean is either a run- ning vine, trained on frames, bushes, or poles, or a bushy shrub growing one or two feet high, and requires a rich, well prepared soil, which it does not exhaust, and in which it grows rapidly and luxuriantly. It bears a pod con- taining several oblong, rounded seeds, which are used when soft and green, or, when dry, ground into meal or softened by soaking in Kidney Bean (Phaseolus vulparls). water and boiling or baking. Beans are highly nutritious, containing 84 per cent, of nutri- tious matter, while wheat has but 74 per cent. For horses this food is more nourishing than oats. Baked beans are a healthful, strength- ening, and favorite dish throughout the north- ern states, especially in rural regions ; and in France and in the United States several va- rieties are cooked and eaten with the green pods, while French beans and pods are cut up and salted for winter use in Germany and Hol- land. The garden and field beans brought to market have a variety of names, among which the Lima, Windsor, dwarf, and kidney are favorites. In ancient times beans were used as ballots, white for affirmative and black for negative. Ovid gives a description of an im- portant ceremony, in which the master of a family, after washing his hands three times, throws black beans nine times over his head, with the words "I redeem myself and family