CONDOR 



1528 



CONE 



Estimating. Sand and stone arc bought by In the larger museums, ifeondor eggs have 



the cubic yard, cement in sacks of 100 pounds 

 containing slightly less than a cubic foot. After 

 water is added the three elements will shrink 

 to about eighty per cent of their original vol- 

 ume. Multiply the distance around the house 

 in feet by the height and again by the thick- 

 ness of the foundation in feet, then divide the 

 result by twenty-seven to get the number of 

 cubic yards. One cubic yard of sand, two 

 cubic yards of stone and ten sacks of cement 

 will make about two and two-thirds cubic 

 yards of concrete. C.H.H. 



For further Illustrations of concrete structures, 

 see BRIDGE. Consult Hood's Reinforced Concrete 

 Construction; Taylor and Thompson's Concrete, 

 Plain and Reinforced. A journal devoted to con- 

 crete is Concrete and Cement Age. 



CON 'DOR, the largest known creature of the 

 air, a bird of prey, keen of sight and smell, 

 wonderfully graceful in flight, but with habits 

 disgusting and cowardly. The native home of 

 the condor is the South American Andes, but 

 in the mountains 

 on the Pacific 

 coast of the Unit- 

 ed States there 

 was once one 

 larger than all 

 the others. Its ex- 

 panse of wing was 

 more than the 

 usual ten feet of 

 the South Ameri- 

 can species, and 

 it was longer than 

 fifty inches. Like 

 the South Ameri- 

 can condor it was 

 black, with white 

 tinged wings, but 

 it was without THE CONDOR 



the downy ruff of white feathers. Instead, it 

 had a fringe of black feathers on the back of 

 the neck, which made it look very savage. 

 The condor's head and neck are covered with 

 dull red skin, folded in great wrinkles. The 

 male has a comb and wattles of red skin. 



Condors nest among the rocks of high cliffs. 

 They come down to feed on dead animals and 

 decaying flesh, but they also attack sick or 

 helpless animals which are unable to defend 

 themselves, and they gorge themselves to such 

 an extent that they become helpless and can 

 be lassoed while feeding. The condor lays two 

 white eggs in a high cliff nest of a few sticks. 



brought as high as $100 each. 



CONE, kohn, a solid whose base is a circle, 

 and whose convex (outward-curving) surface 

 tapers uniformly to a point called the vertex. 

 The cone generally used in practical problems 

 is the right circular cone, in which the line 



Vertex 



Cone frustum of a Cone 



drawn from the vertex to the center of the 

 base is perpendicular to the base. The per- 

 pendicular distance from the vertex to the 

 center of the base is called the altitude of the 

 cone; the distance from the vertex to the 





perimeter of the base is its slant height. The 

 frustum of a cone is the portion left after the 

 top is cut off on a plane parallel to the base. 

 Rules and Problems. (1) The volume of a 

 cone is equal to one-third the volume of a cylin- 

 der which has its base equal to the base of the 

 cone, and its altitude equal to the altitude of the 

 cone. This can be observed from the following 

 experiments : 



