230 



SCIENCE 



[N. S. Vol. XLII. No. 1077 



The American army may establish local 

 self-government in Cuba from the highest 

 of humanitarian motives, or it may wage a 

 war of conquest on a weak neighboring 

 country from the low motive of increasing 

 the power of human slavery as a national 

 institution. 



From our experiences upon the earth we 

 iave learned to place faith in certain simple 

 laws of nature, amongst which are the 

 following : 



1. Every particle of matter attracts every 

 other particle of matter, in accordance with 

 the law of gravitation. 



2. Heat always flows from a hotter body 

 to a colder body. 



3. The volume of a given quantity of gas 

 or vapor is a function of the temperature 

 and pressure to which it is subjected. 



If a rifle, elevated at a certain angle 

 above the level surface of a lake, gives a 

 certain muzzle velocity to the buUet, the 

 bullet will describe the curve which the 

 law of gravity says it should describe, and 

 strike the water where the law says it should 

 strike, provided we take into account two 

 small factors that are also acting — the re- 

 sistance of the air and the rotation of the 

 earth. 



A red-hot cannon ball and a red-hot bul- 

 let, thrown into a great bank of snow will 

 both cool down to 32° Fahrenheit; the great 

 cannon ball slowly and the little buUet 

 rapidly. 



A rubber balloon containing a given 

 quantity of hydrogen gas can be so propor- 

 tioned that if thrown from a high tower on 

 a hot summer day it will expand and rise, 

 or on a cold winter day it will contract and 

 faU. 



If a comet, a hundred million miles away, 

 more or less, is observed very accurately as 

 to its direction from us to-night, again next 

 Monday night, and a third time in two 

 weeks from to-night, Newton's law of gravi- 



tation wiU enable us to determine the curve 

 in which the comet is traveling around the 

 sun, and to say where the comet may be seen 

 three months or six months later. 



The great stars and the small stars radi- 

 ate their heat energy into surrounding 

 space: the great stars cool off extremely 

 slowly, and the small stars comparatively 

 rapidly. Examples of this principle, it is 

 believed, are the great sun, on the one hand, 

 its volume 1,300,000 times the earth's vol- 

 ume, its surface temperature higher than 

 10,000° Fahrenheit, and its interior tem- 

 perature immensely higher yet; and the 

 little earth, on the other hand, cool on the 

 surface and relatively cool in the interior. 



As the great gaseous suns radiate their 

 heat energy unceasingly into surrounding 

 space, they undoubtedly grow slowly 

 smaller under the force of their own inter- 

 nal gravitation which strives constantly 

 to pull each molecule of gaseous matter to 

 the centers of the stars. 



There is every reason to believe that the 

 three simple laws which we have quoted and 

 illustrated are fundamental, and operate 

 invariably throughout the stellar universe. 



And so it is, as far as human experience 

 has gone, with all the laws of nature. 



To some people this infallible and uni- 

 versal obedience to law — the strict ac- 

 countability of effect to cause — seems a 

 hard and cruel fact and counter to ideal- 

 ism in its various forms. This is a hasty 

 and faulty view. It is the cause-and-effect 

 relationship which gives us something de- 

 pendable upon which to build our civiliza- 

 tion. The recognition of this principle, 

 whether conscious or unconscious, is the 

 chief difference between modem civiliza- 

 tion and the civilizations which prevailed 

 in the days of the inquisition and of the 

 Salem witchcraft. Looking at the subject 

 from the idealistic standpoint, the concep- 

 tion that all matter in the universe is en- 



