20 TENTH ANNUAL REPORT OF 



ant part of the duty of this Institution to encourage special lines of 

 research into every department of the varied domain of nature. 

 Though it might be a perversion of intellect for a large number of 

 23ersons in the same country to occupy themselves in any one pursuit 

 of this kind, when so much on every hand is required to be done, yet 

 it is highly meritorious in any individual to devote himself systemati- 

 cally, industriously, and continuously, for years, to the elucidation of 

 a single subject. He may be said to resemble in this respect the ex- 

 plorer of an inhospitable region, who enables the world to see through 

 his eyes the objects of wonder and interest which would otherwise be 

 forever withdrawn from human knowledge. Let censure or ridicule 

 fall elsewhere — on those whose lives are passed without labor and 

 without object ; but let praise and honor be bestowed on him who 

 seeks with unwearied patience to develop the order, harmony, and 

 beauty of even the smallest ^^art of God's creation. A life devoted 

 exclusively to the study of a single insect, is not spent in vain. No 

 animal, however insignificant, is isolated ; it forms a part of the great 

 system of nature, and is governed by the same general laws which 

 control the most prominent beings of the organic world. 



It is proposed to publish this paper in a number of parts, com- 

 mencing with the oology of the birds of prey. This is one of the 

 most difficult of all the families to study with precision, on account 

 of the retiring habits of the birds and their almost inaccessible breed- 

 ing places. 



6. The next paper is on the relative intensity of the light and heat 

 of the sun upon the different latitudes of the earth, by L. W. Meech, 

 Esq. This memoir, which was submitted for examination to Prof. 

 Peirce and Dr. B. A. Gould, of Cambridge, presents a thorough mathe- 

 matical investigation of the only known astronomical element of me- 

 teorology. It gives a distinct^ precise, and condensed view of this 

 element ; enables the practical meteorologist to compare it with the 

 results of observation ; to eliminate its influence and obtain the resid- 

 ual phenomena in a separated form and better fitted for independent 

 investigation. It determines, from the apparent course of the sun, 

 the relative number of heating and illuminating rays which fall upon 

 any part of the earth's surface. The rays of light and heat from the 

 sun to the earth, though imperceptible in their passage through free 

 space, and manifest only by their results at the surface of the globe, 

 evidently constitute a primary element of meteorology. The subse- 

 quent effects , which are measured by the thermometer and designated 

 by the word temperature, are secondary, and modified by a variety of 

 proximate causes. In accordance with tliis distinction, the numerous 

 researches in this field may be divided into two classes, namely, those 

 which relate to the number of rays falling on a given phice, and those 

 which relate to the temperature produced by these rays under different 

 conditions of surface, &c. To the former of these belongs the investi- 

 gation of Halley, given in the Philosophical Transactions for 1G93. 

 By regarding heat as of the nature of force and resolving it into a 

 horizontal and a vertical component, he drew the proi)er distinction 

 between the number of rays and their heating effector "impulse," 

 which is expressed in the well known law, that the sun's intensity at 



