MOLECULE 



3878 



MOLIERE 



not unlike those of a mole, and usually with 

 short wings, which, however, may be entirely 

 absent. These crickets spend their lives under- 

 ground, and travel in burrows of their own dig- 

 ging. Their food is larvae and earthworms, and 

 they destroy the roots of plants. The female 

 lays from 200 to 400 eggs. In Porto Rico these 

 insects are called changa, and there they cause 

 great damage to vegetation and crops. 



MOLECULE , mol ' e kule, in theory, the small- 

 est physical unit into which matter may be di- 

 vided. A molecule of water, for example, is the 

 smallest possible particle which retains its iden- 

 tity as water. The molecule, which cannot be 

 further divided by crushing or grinding or by 

 the application of any mechanical or physical 

 force, can be broken up by chemical action into 

 the parts which unite chemically to form it; 

 these parts are known as atoms (see ATOM). 

 Sometimes the atoms are all of one kind, in 

 which case they unite to form an element; oxy- 

 gen, for example, is an element, because its 

 molecules are formed by the union of similar 

 atoms. Many times, however, atoms of differ- 

 ent kinds unite to form a molecule, and the re- 

 sult is a compound; water is a compound, since 

 each molecule of water is made up not of water 

 but of atoms of oxygen and hydrogen. These 

 atoms are in the proportion of two atoms of 

 hydrogen to one atom of oxygen; this combi- 

 nation is symbolized as H2O. In the composi- 

 tion of matter, atoms unite chemically to form 

 molecules, and molecules unite physically to 

 form mass. 



A molecule, of course, has never been seen, 

 even under the most powerful microscope. This 

 is not surprising when one stops to consider that 

 the molecules that unite to make up a volume 

 of gas as large as the head of a pin are thirty 

 million times as numerous as the people who 

 inhabit the globe. In no laboratory, then, has 

 a molecule ever been physically separated from 

 its fellows. Scientists, however, need a unit in 

 conducting their work, and so they have im- 

 agined this tiny, ultimate bit of matter and 

 called it a molecule. 



Molecular Force. Molecules are held together 

 by a mutual attractive force not unlike that of 

 gravitation (which see). As with the sun and 

 planets, this force acts most strongly when the 

 molecules are nearest together. In a solid the 

 molecules are so close together that they can 

 move very little, and the definite form of the 

 body is not readily changed. In fluids the 

 molecular force is less; the molecules change 

 their relative position easily, and the substance 



has no definite shape. In gases the force is so 

 slight that the molecules tend to fly apart and 

 expand as widely as possible. Water is a sub- 

 stance which appears in all three states; as a 

 solid (ice), as a liquid and as vapor (steam). 

 Heat affects the force with which the compo- 

 nent molecules attract one another; the degree 

 of heat present determines whether water shall 

 have a fluid, a solid or a gaseous form. 



Molecular Weights. Gases, like solid bodies, 

 have weight. The relative weight of the mole- 

 cules composing them is determined by weigh- 

 ing like volumes of two gases and assuming 

 that they contain the same number of mole- 

 cules. A given volume of hydrogen is lighter 

 than a like volume of any other known sub- 

 stance; consequently it has been found con- 

 venient to adopt it as the unit of measurement 

 and call its molecular weight 2, since each mole- 

 cule is composed of two atoms whose weight is 

 regarded as 1 each. Other gases are said to be 

 so many times heavier than hydrogen. In the 

 study of chemistry, many other ways of deter- 

 mining molecular weight are given. Some ap- 

 proximate molecular weights follow: 



Hydrogen 

 Oxygen . . 

 Water . . . 

 Sulphur .. 

 Ozone . 



32 



18 



64 



..48 



Nitrogen 28 



Salt 58.5 



Caustic soda or so- 

 dium hydroxide 40 



G.L. 



See CHEMISTRY; ATOMIC THEORY. 



MOLIERE, molyair' (1622-1673), the name 

 by which the greatest of French dramatists, 

 JEAN BAPTISTE POQTJELIN, is known in the liter- 

 ary world. Of the dramatists who have lived 

 since the beginning of the modern period he 

 ranks next to 

 Shakespeare, and 

 in his power to 

 combine humor 

 and pathos is 

 often compared 

 with the great 

 English genius. 

 Moliere distin- 

 guished himself 

 as a writer of so- 

 cial comedy. That 



is, he gave an ac- 

 curate picture of 



MOLIERE 

 Among modern dramatists 



f r, he ranks next to Shakespeare, 

 the society of his but the average English 

 day, satirizing in reader knows little of him. 

 brilliant and vigorous dialogue the weaknesses 

 and foibles of the men and women about him. 

 The humorous effect of his plays is obtained 

 through the portrayal of character rather than 



