GLOSSARY 



Pre cip'i tate, an insoluble compound formed sometimes when, 

 soluble compounds are poured together. If hydrochloric acid is 

 to a solution of lead nitrate a white precipitate of lead chloride will 

 be formed. 



Ra'di um, an intensely radio-active, metallic element found in minute 

 quantities in pitchblend and carnotite. Some is found in the state 

 of Colorado. It has the property of giving off light, etc. 



Rare air, air that weighs less per unit volume than air at sea level, or 

 air that is less dense than some other air. A cubic foot of air on top 

 of a mountain three miles high weighs only one-half as much as a 

 cubic foot of air at sea level. 



Re frig er a'tion, a process by which foods are kept at a low temperature 

 so that they do not spoil very rapidly. Meat, eggs, fruit, and vege- 

 tables are often kept in cold storage or refrigerator rooms. 



Retting, a process of preparing flax plants by soaking them in water. 

 It causes the soft parts of the stems to decay and then the fiber is 

 combed. 



Sa li'va, the digestive fluid secreted by six small glands and poured into 

 the mouth in large quantity while one is eating; at other times a 

 sufficient amount is secreted to keep the mouth moist. It contains 

 an enzyme, ptyalin, which can change starch to sugar. 



Saturated solution, a liquid containing as much of another substance 

 as it can hold in solution. When water has all the dissolved salt or 

 sugar that it can hold, it is a saturated solution. 



Sed'en ta ry, when applied to a man, means one who does not take 

 much physical exercise. Bookkeepers and stenographers lead a 

 sedentary life. They should take exercise in the open air when 

 possible. 



Seedling, a young plant in the germinating stage. 



Si'sal, a kind of hemp of which rope is made. It grows in Mexico and 

 in Central America. 



Ster'i lize, to treat tools and substances in such a way that living 

 organisms, disease germs, are killed. Boiling water and chemicals 

 are used for this purpose. 



Tho rac'ic duct (thoras'ik), a tube just inside the spinal column. It 

 extends from back of the middle of the digestive organs to the left 

 side of the neck, where it connects with a large vein coming down from 

 the head. The digested fat, and lymph (a milky-colored liquid from 

 many parts of the body) pass into the blood through this tube. 



Volt, a unit of electromotive force. It is an electromotive force which 

 will drive a current of one ampere over a conductor which has a resist- 

 ance of one ohm. 



Water sprouts, branches which appear around the base or on large 

 limbs of trees. They should not be left on trees because they make 

 them too bushy, waste the food of the trees, and bacteria diseases 

 can easily enter the trees through them. 



