July 24, 1885. 



SCIENCE. 



65 



charm as the best age of Greece. To the 

 specialist the remotest problems of science, 

 doubtless, come to have living interest, become 

 a part of his life, in fact ; but they are not so 

 to the beginner. 



After some sense of the present conditions 

 of the earth's surface is gained, the youth may 

 be shown the evidences of the earth's past. 

 It is particularly desirable that this inquiry into 

 the old conditions of the earth should be so 

 made as to aid the student to conceive the an- 

 tiquit}' of the earth's past. This conception 

 of past time is the most dilfficult to form of any 

 of the large understandings of nature, while at 

 the same time it is the most enlarging idea 

 that can be obtained from geology. It gives 

 much that will re-act on the youth's under- 

 standing of human histor3\ If on viewing the 

 slow gain of man in his progress from age to 

 age, the persistence of evil beneath the guise 

 of changed manners, and the inevitable sink- 

 ing into the pit which seems in time to over- 

 take all peoples, there comes to the student 

 that sense of helplessness which so often as- 

 sails the most ardent believers in the future of 

 humanit}', the geologic past has consolation 

 for him. There he sees that ' one eternal pur- 

 pose runs ' through all those ages, and that the 

 very catastrophes which seem to bring tempo- 

 rar}' ruin are but the steps to new life. Even 

 more valuable than this is the impression of 

 amplitude of time, which the student needs to 

 secure as the basis on which to rest all his un- 

 derstandings of nature. Measuring the prog- 

 ress of all events from the infinitesimally brief 

 duration of human life, the student is prone to 

 impatience with the slowness with which this 

 march of the ages goes on. Give him a sense 

 of the larger space of the earth's history, and 

 we relieve the mind of this prejudice. 



Beyond the realm of the earth, it is not 

 worth while to try to do much. Astronomy 

 has, however, some tolerably simple and most 

 important lessons. Its greater truths are un- 

 fortunately only accessible through the way of 

 rather difficult mathematics ; but there are some 

 conceptions which are to be obtained with little 

 labor, and which should be won. The order 

 of the solar system, and the relations of the 

 several planetary bodies, should be within the 

 compass of minds entirely unskilled in mathe- 

 matics. The first of these relations to be 

 studied should be that which is found in the rev- 

 olution of the earth around the sun, and the 

 concomitant efifects derived from the increase 

 and diminution of eccentricity of its orbit, the 

 precession of the equinoxes, and the rotation of 

 the apsides. With a small globe (or, as well. 



an orange), with pins to represent the poles, 

 and a thread for the equator, a lamp on a 

 centre-table to represent the sun, and a little 

 exercise of limbs and wits in convej^ing the 

 sphere around the table in a way to imitate 

 the phenomena in question, the student can 

 gain a clear conception of a most important 

 series of relations. The student should then 

 proceed to the work of extending the same 

 order of conceptions to the other bodies of the 

 solar system. 



As in geology the student finds a profit in 

 the expansion which the conception of vast 

 duration forces upon the mind, so in the study 

 of astronomy enlargement may be gained by the 

 conceptions of space which are brought home 

 to him in the studj^ of that science. Neither 

 geologic time nor celestial space can really be 

 conceived b}^ the mind ; still, the eff'ort to grap- 

 ple with such immensities, though seemingly 

 futile, is yet profitable. Especially if it be 

 often repeated, this efli'ort bears fruit in a sense 

 of power which is given by no other mental 

 exercise. Manj^ things ma}^ give breadth to 

 the mind, but among these widening agents the 

 conceptions of time and space deserve high 

 rank. It would be in a certain way true to say 

 that we might get a measure of the greatness 

 of a mind by its power to conceive a wide field 

 of temporal and spacial relations. May we say 

 that these measures enter the soul, and give it 

 something of their dimensions? 



We turn now to the use which we may make 

 of nature when we seek to give the mind a 

 conception of the relations of cause and eff'ect, 

 and the nature of evidence. The best field for 

 such study is to be found in the department of 

 physics and chemistry. There we may in many 

 cases so isolate the phenomena we are exam- 

 ining, that they are uninfluenced by other con- 

 ditions than those which can be perceived and 

 taken into account. Studies in this field should 

 begin with the phenomena of masses, with the 

 eflTects of gravity, of momentum, and other 

 actions where the facts are in the realm of tol- 

 erably familiar experience. Such personal ex- 

 periences should be multiplied until the mind 

 becomes habituated to the actions which it is 

 contemplating. From this firm ground, studies 

 should be extended to the obscurer phenomena 

 of physics, or such as are found in those parts 

 of the subject where the causes are invisible, 

 as in the great field of electrical action. There 

 the mind can become accustomed to the consid- 

 eration of causes which are not onlj" invisible, 

 but outside of the limits of ordinary experi- 

 ence. 



After some training in this department, the 



