CALABASH 



1047 



CALAIS 



sary to use what is termed a pneumatic caisson. 

 First, a metal caisson open at one end and 

 with cutting edges is sunk into the water, 

 bottom side up. On this is placed another 

 caisson open at the top, and in this the desired 

 masonry is built, thus driving the lower caisson 

 further into the ground. After this is begun 

 compressed air is forced into the lower caisson 

 until the water inside is forced into and out 

 through the earth beneath. Then men are 

 sent into the space inside the caisson through 

 an opening called an air lock, and they con- 

 tinue digging out the earth inside the walls 

 of the casing until the surface is reached on 

 which it is desired to have the foundation rest. 

 The conditions under which these men work 

 are similar to those under which a diver works. 

 The masonry above has grown as the hole be- 

 low has grown deeper, and finally rests on the 

 rock bottom prepared for it. A similar use of 

 the caisson is common in excavating tunnels 

 under rivers. In this work, however, the caisson 

 is driven horizontally. The great railway tun- 

 nels under the Detroit River at Detroit and 

 under the Hudson River at New York were 

 excavated by this method. See TUNNEL. 



In sinking foundations for very large 'build- 

 ings a caisson open at both ends, the lower 

 end with cutting edges, is forced into the earth. 

 The caisson sinks lower as the earth inside 

 is removed. When rock bottom is reached, 

 the caisson is filled with concrete. In this 

 manner a concrete pillar resting on solid rock 

 is secured. Most of the "skyscrapers," or very 

 tall buildings, rest upon foundations of this 

 sort. 



Caissons, of various forms and in various 

 combinations, are used for raising ships out of 

 the water, and also for floating docks. Coffer- 

 dams (which see) are used in preference to 

 caissons where a foundation is to be built in 

 shallow water. See DRY DOCK. F.ST.A. 



CALABASH, kal'abash, a name given to a 

 gourd similar to a' squash or pumpkin. It is 

 an annual, cultivated in the same manner as 

 a squash. The smooth, hard shells are dried 

 and used as vessels for holding liquids. 



Calabash Tree. This must not be confused 

 with the calabash mentioned above. It is 

 an evergreen tree growing in South America, 

 which bears a gourd-like fruit. The shell is 

 very hard and tough and is >used for domestic 

 utensils of many kinds. For boiling water it 

 can be placed over a fire many times without 

 being burned. The wood of the tree is used 

 for coach building. 



Calabash Pipe, a tobacco pipe made from 

 the stem of a calabash of the squash variety 

 and considered by many smokers to be the 

 mildest and sweetest kind of pipe. It is of 

 comparatively recent origin, the "invention" 



CALABASH: GOURD AND PIPES 

 (1) Calabash as grown; (2, 3) pipes with 

 stems of differing curves, resulting from varying 

 curves in the gourd. 



of a British soldier in South Africa during 

 the Boer War. Having broken the bowl of 

 his pipe he hollowed out the thin end of 

 a calabash gourd and attached a mouthpiece 

 to it. Calabash pipes are now in great demand 

 and are sold at prices ranging from $5 to $25. 

 CALAIS, kalay' or kal'is, a seaport and 

 manufacturing town of Northern France, the 

 nearest continental city to the British Isles. 

 It is important as the chief port for passenger 





^ vre FRANCE 



LOCATION OF CALAIS 



traffic between France and England. The town 

 is in the Department of Pas-de-Calais, twenty- 

 five miles southeast of Dover, England, and 

 185 miles north of Paris. 



