ASTRONOMICAL AND PHYSICAL OBSERVATORIES. 369 



connect isolated facts is much more valuable. Viewed in this light, 

 the study of astronomy will he readily seen to he less efficient for 

 training the mind than the study of physics. Physics, indeed, in- 

 cludes astronomy as one of its parts, hut, as the termph ysics is com 

 monly used, it denotes the science of the changes and conditions of 

 terrestrial matter, and peculiarly of the laws relating to the various 

 emanations of celestial bodies, heat, light, etc. The subjects here re- 

 ferred to are such that their study requires in the very highest degree 

 just those faculties which it is the province of modern education to 

 train. Physics, too, is eminently a practical science ; it gives the ra- 

 tionale of what we see all around us, and is, so to say, of progressive 

 difficulty. Its elements may be taught to the young lad, and he may 

 go on for his life in their development. Every special method which 

 is useful educationally, that we have referred to in astronomical study, 

 has its analogue here. 



Thermo-dynamics and optics certainly present as wide fields for 

 pure analysis as even celestial mechanics. In the cultivation of the 

 powers of observation, the study of physics stands preeminent ; and 

 in the physical laboratory the student has an immense advantage, for 

 in many cases it is within his power to produce by experiment, and on 

 a small scale and under favorable conditions, the same appearances 

 that he observes in Nature. There is thus opened to the mind a vast 

 field for that " scientific use of the imagination " which is so important 

 an element in culture. 



Perhaps it is more than time that the exact nature of a physical 

 laboratory or observatory should be explained, and we are fortunate 

 in having a succinct account of its main purpose from the hand of 

 Prof. Henry, of the Smithsonian Institution. 



Prof. Henry says (Report, 1870, p. 141) the principal object of a 

 physical observatory is, "to investigate the nature and changes of the 

 constitution of the heavenly bodies ; to study the various emanations 

 from these, in comparison with the results of experiments, and to re- 

 cord and investigate the different phenomena which are included under 

 the name of terrestrial physics." 



The study of the nature and constitution of the sun, by means of 

 photographs, by experiments on its heat, by the spectroscope, and the 

 comparison of these results with similar observations of the stars, is 

 also pointed out by Prof. Henry, as among the legitimate and neces- 

 sary works of such an institution as he describes. Climatology, me- 

 teorology, magnetics, and electrics, equally belong to its scope. 



To completely equip such an observatory as we imagine, would 

 require a great outlay, but, considered only in its relation to a college, 

 an equipment becomes much more simple and less expensive. The 

 apparatus required is simple in its nature, and but few of the single 

 instruments are of great cost, and the true policy of a college would 

 be to allow its laboratory to grow slowly with it, enlarging its scope 

 vol. 11. 24 



