and dismay which attacked the strongest hearts on the approach of a 

 comet, and more especially upon the astronomical prediction of the return 

 of the great comet of 1264 to cross the earth's orbit at a point near the 

 actual position of the earth, seems to have been groundless. It was stated 

 on high authority that a collision with a comet would " shiver the earth to 

 atoms and diffuse it throughout space." But we now know that such a 

 collision with a comet takes place every thirty-three years, and is only a 

 grand display of fire-works. It takes place in fact, to some extent, twice 

 every year, and possibly three or more times. However harmless such 

 collisions are upon the constitution of our planet, we are convinced that 

 the impact of such bodies upon our atmosphere must generate large quanti- 

 ties of heat, and thus have an important influence upon the general forma- 

 tion of cyclones. What the specific form this influence may be, it remains 

 for the science of Meteorology to investigate and determine. Thus not 

 only the phenomenon of the restoration of equilibrium between the upper 

 and lower strata of the atmosphere demands the attention of the student 

 of Meteorology, but he must note the disturbing elements that arrive from 

 the remote regions of space. He must note especially the cyclones and 

 vast upheavals in the sun which appear as spots and protuberances on its 

 surface, and seem to be connected in some mysterious manner with the 

 phenomena of the aurora borealis, of earthquakes, of the variations of the 

 magnetic needle, and of the electrical currents moving round the earth. 

 The doctrine of the correlation of forces, now adopted by all physicists, 

 will perhaps, in time, lead us to the exact knowledge of conditions under 

 which heat, light, electricity, and magnetism, undergo metamorphoses 

 into each other. 



The prevailing tendency of the science of our age is s^-nthetic. It places 

 before itself the problem of combination and generalization. While special 

 analytic studies are pushed out on all hands by troops of physicists, each 

 one desires to see the modifying result of his researches upon the net total 

 of previous observation. 



It is to be expected that the study of the physical conditions of the life 

 of man will always attract most attention. At present this phase of Natu- 

 ral Science takes three directions. The first is that of the natural history 

 of Man, its various tendencies being grouped together under the head of 

 Ethnology. One class of observers, like Tylor and Lubbock, study the 

 stages of man's prehistoric life through what geological evidence comes to 

 light. Another class investigate the question of the transmutation of the 

 species under natural conditions and organic reaction or adaptation. Dar- 

 win and his extensive school, together with their opponents, occupy this 

 field. Secondly, there is the physiological school, which likewise includes 

 two classes, one — headed byVirchow, Huxley, Bastian,and others — study- 

 ing the subject of cell-growth and spontaneous generation : another branch 

 noting carefully the correlation between the mental and physiological phe- 

 nomena. This school is represented by Bain, Maudsley, and others. Then 

 there is another class devoted to Sociology in its various phases : Quetelet 



