PLANT JUICES, THEIR COMMERCIAL VALUES. 203 



places. There is thus danger of the product failing, and at no very 

 distant date, unless enlightened governments interpose to replant the 

 forests destroyed. Perhaps the most important use to which gutta 

 percha is put is the insulating of submarine cables. Without this 

 substance, which is wholly impervious to and indestructible by water, 

 our ocean cables could never have been laid. For piping it is also in- 

 valuable, not contaminating water as lead pipes do. Its acoustic 

 properties call for its use in speaking tubes, telephones, etc., as well 

 as in ear and lung-testing instruments. For funnels, siphons and 

 chemical apparatus, it is found in every laboratory. It burns with a 

 bright flame, like sealing-wax. When cold and hard it is much less 

 elastic than India rubber, and keeps, when hardened, any impression 

 made upon it while soft, even the finest lines. Its use is thus indi- 

 cated in electrotyping. It is farther used in solution, as a varnish of 

 great lustre and brilliancy, taking graining in imitation of oak or other 

 woods. Gutta cannot be obtained from a tree until it is thirty years 

 old, when its yield may be from two to three pounds a single tree. 

 The tree is slender-stemmed, measuring one and a half to three feet 

 around and growing from 100 to 140 feet high. Many of the Euphor- 

 bias contain more or less gutta in their milky juice. 



Of oils and fatty substances, olive, castor and palm oils are 

 examples. Our most prized salad oil is squeezed from the pulp of the 

 olive fruit, of Olca Etiropca, and other species of the olive tree. The 

 oil is found in sacs just under the skin. This gives rise to an immense 

 industry. In Nice there are 15,000 acres planted in olives, producing 

 from 180,000 to 200,000 gallons of oil annually. In Tunis there are 

 5,000,000 trees which produce 44,000 gallons of oil yearly. Persia 

 raises 100,000 cwts. of fruit. Although Syria is the home of the olive, 

 all the countries bordering on the Mediterranean are covered with the 

 gray green of this pretty tree. Once planted it needs no cultivation, 

 and it grows well on steep, rocky lands, up on the high hills and down 

 in the valleys. It is a tree of slow growth and of great age. It grows 

 from cuttings stuck into the ground, and hammered down with a 

 stone. The juice is expressed from the fruit by mills. At first the 

 oil is dark and muddy, but the impurities will settle after being al- 

 lowed to stand a while, when the top becomes clear, amber colored, 

 delicate in taste. In the fall the shores of the Adriatic are alive with 

 donkeys and mules taking the oil in casks or skins on their backs to the 

 ships which dot the harbor bound for every port in the world. A great 

 deal is brought to America. Florentine Oil is considered the best. 



Linseed oil is used in paints and varnishes, also in printer's ink. 

 Hundreds of tons of printer's ink are made from this oil, which is ex- 

 pressed from flaxseed by heating and other processes. 



