to induce as many individuals as possible, in various parts of the country, to devote their leisure hours to special objects of natural history-to point out to them the pleasures derived from studies of this kind systematically pursued, and the important results which will flow from their labors when combined with those of other persons in the same line, and also to facilitate by catalogues, descriptions, and correspondence, the progress of the student in the elementary part of his studies. In connexion with this object, circulars have been distributed directing special attention to different points, among which we may mention one on American grasshoppers, an insect to the ravages of which a large portion of the United States is frequently subjected, and relative to which every well authenticated fact is of considerable interest. Another circular has been issued in regard to the collection of nests and eggs of birds, to furnish the material for a continuation of Dr. Brewer's work on Oology.

The fact was stated in a previous report that materials had been collected for a new edition of a report on the libraries of this country, originally prepared by Professor C. C. Jewett. This work was entrusted to Mr. William J. Rhees, chief clerk of this Institution, to be done out of the usual hours of his official duties; but the materials which were collected contained so much information relative to educational and other institutions, which was thought too important to be omitted, that the report when completed was found to exceed the limits assigned by the Institution; and rather than abridge it by leaving out a part of the material which had cost so much labor, Mr. Rhees offered to publish it on his own account; and such an arrangement being compatible with the general policy of the Institution, the proposition was agreed to, and the work has accordingly been issued under his own name and responsibility. It forms a volume of 700 octavo pages, and contains a large amount of very interesting and valuable" matter which has cost the author a much greater amount of labor than can ever be repaid by even an extensive sale of the work.

In this connexion we may mention that a list of the libraries, societies, and institutions in North America, has also been prepared by Mr. Rhees and printed for the use of the Institution. It forms an octavo pamphlet of 81 pages, and is found of much value in facilitating the distribution of our several classes of publications and in directing circulars, &c.

Researches.-Mr. L. W. Meech has continued his mathematical researches in regard to the light and heat of the sun, and, since the date of the last Report, has succeeded in integrating some of the analytical expressions which had previously appeared likely to prove exceedingly troublesome, and the analysis is now sufficiently advanced for another publication. His next memoir will treat of the relative intensity of the sun's rays after passing through the air to the earth's surface. It will be recollected that his former memoir presented, in tables and curves, the intensity of the sun's rays at the exterior of the atmosphere. The primary formula, to be given in this memoir, has been demonstrated and verified, and the derived formulæ are mostly made out for the range and other phases of the intensity of the light and heat. These depend on what are called elliptical functions, and are much more complicated than those of the former paper. Before curves can be drawn from them, the numerical values for every five degrees of latitude are to be computed and checked, which will require the labor of several months. To defray the expense of this, another small appropriation will be required. The success of the previous labors of Mr. Meech warrants this expenditure, from funds intended for the increase of knowledge, since the results which can now be obtained from his formula will, in all probability, be consid ered standard elements in the physical theory of heat.

Dr. Wolcott Gibbs has continued his chemical researches, and a paper in relation to them will probably appear in the next volume of Contributions. It will present new processes for the separation of all the platinum metals in a state of absolute purity. These are very simple, and easy of execution, and not only apply to the separation, but to the quantitative analysis of mixtures of the different metals of this group in almost any proportion. The researches also involve the preparation and properties of a new and remarkable series of salts, which, it is thought, will remove the difficulties with which the subject has hitherto been surrounded.

It was stated in the last Report that one of the most important operations in which the Institution had been engaged during the previ ous year was the construction of a map to present at one view the arable, forest, and sterile portions of the United States. The design. at first was merely to exhibit the limits or boundaries of these portions of the country, and this has been faithfully executed by Dr. J. G. Cooper, to whom the work was intrusted, as far as the materials

could be gathered from all the accessible published data, the records of the Land Office, and other sources. The facts presented at once to the eye by this map are in striking accordance, as we have before mentioned, with the deductions from the meteorological materials which have been collected at this Institution, and serve to place in a clear point of view the connexion of climate with the natural productions of different parts of the earth. The plan has, however, since been enlarged, and Dr. Cooper now proposes, with the aid of the Institution, to construct a map which shall give in detail the distribution of the several kinds of trees and shrubs found in different portions of the country; and, in view of this, he has prepared an article, which has been published and widely distributed by the Institution, containing a list of the localities of the most important and useful trees and shrubs, as far as known, and asking additional information. The chief difficulty in carrying out the plan has been the want of definite knowledge as to the locality of different plants; for example, a plant is mentioned as occurring in Virginia, but this statement is not sufficiently precise, since this State occupies a large surface, on a small portion of which only the plant may be found. Facts are also required as to the abundance of trees in a given locality.

The collection of the material for a map of this kind, in connexion with a work on the forest trees of America, still in progress by Dr. Asa Gray, of Cambridge, is a very important matter both in a political and an economical point of view, and the work might be materially aided, without much expense to the government, by appending a few additional queries to the questions propounded by the marshals who collect the statistics of the census. The outline map, which has already been prepared at the expense of the Institution, has excited much interest, and the proposition to enlarge the plan of the work has been received with commendation.

As an interesting object in regard to physical geography, and intimately connected with meterology and various branches of natural history, a commencement has been made, in connexion with the Coast Survey, in collecting materials for the construction of a hypsometrical map of the United States.

No part of the surface of the earth, of equal dimensions, has been so extensively traversed by lines of explorations for canals, railways, and river improvements, as the United States. The materials, however, which are afforded by these, for constructing a map of the ele

vations and depressions of the surface of the country are widely scattered, and unless an effort be made to collect them will ultimately be lost. Previous to the connexion of the Institution with this enterprise, circulars were sent by the Coast Survey to engineers and directors of public works, in answer to which replies were received giving the elevation of a large number of points. Since this connexion another circular has been issued, to which a large additional number of answers have been received. The whole number of points heard from is about 9,000. Many of the replies to the circulars have been accompanied by valuable topographical information and maps, some of which, as testified by the contributors, were rescued from the oblivion which has been the fate of the records of many of the earlier surveys. For the exhibition of these points, in connexion with the topography of the country, it is proposed to have them plotted on a map consisting of two sheets, with a projection of One sheet is to show the surface east of the Rocky mountains, the lines of water courses, and is to be filled up from the best existing maps; the western sheet is to be copied from the map of the same scale, issued from the office of the Pacific Railroad explorations. An accurate outline map of the United States on this scale will be of great importance as a base-chart on which to delineate the result of various other statistical inquiries which have been instituted by this establishment.

Mr. Lewis H. Morgan, of Rochester, New York, having studied for several years the ethnological peculiarities of the Indians of the North American continent, has discovered among them a system of relationship which he wishes to compare with the systems of consanguinity existing among the natives of other countries, and the Institution, at his request, in order to aid in this research, has distributed circulars to our consuls, missionaries, and ethnologists in various parts of the world. The peculiar system of relationship of the Iroquois, one of the principal families of American Indians first attracted the attention of Mr. Morgan. The fundamental idea of this system, which is carried out with great logical rigor, is, that the bond of consanguinity is never suffered to lose itself in the ever diverging collateral lines—the degrees of relationship are never allowed to pass beyond that of first cousins; after that the collateral lines are merged in the lineal lines, so that the son of a cousin becomes a nephew, and the son of this nephew becomes a grandson. This principle extends upwards as well as downwards, so that the brother of a man's

father becomes his father, and the brother of his grandfather becomes also his grandfather. At first Mr. Morgan supposed this peculiar system to be confined to the Iroquois, but subsequent investigation developed the fact that the same system in its complexity and precision is common to all the Indian tribes of North America. It therefore becomes an object of interest to inquire whether the same system exists among the natives of any other country. It is proper to remark that, at the request of the Institution, General Cass, the Secretary of State, has given to this interesting inquiry the official sanction of his Department, and in a letter appended to our circular, has commended it to all the diplomatic agents of the government abroad.

Laboratory. During the last year the laboratory has been under the direction of Dr. B. F. Craig, of this city, and, as in former years, a considerable number of specimens of the products of different parts of the country have been examined. The policy adopted from the first in regard to examinations of this kind is to furnish a report free of cost to the parties asking for the information, provided it is of general interest and immediately connected with the advance of science, and can be afforded at little expense to the Institution. If, however, the examination is required principally to promote private interests, a charge is made sufficient to cover the expense of the investigation. By the adoption of this policy, the laboratory is kept in operation by means of a small appropriation for chemicals and apparatus.

It may be proper to mention that during the year Dr. Craig has been engaged in investigations, on his own account, in the laboratory, and that Mr. J. H. Lane has made a series of experiments relative to different points connected with the Atlantic telegraph.

Magnetic Observatory.-The remaining instruments necessary to complete the equipment of the magnetic observatory established at the joint expense of the Institution and the Coast Survey were received and put into operation in the early part of the year; but as it has been found that the changes in the direction and intensity of the elements of terrestrial magnetism at Toronto, Philadelphia, and Washington are almost precisely the same, it has been considered that more important service would be rendered to the inquiries now being made in regard to this branch of physics, if the instruments were