sub-brevioribus; floribus subterminalibus magnis purpureis; bacca subglobosâ; seminibus tuberculatis.

"El Paso, southward to the Sandhills; fl. April. Stem 5-6 inches high; spines 4-8 lines long; flower 2-3 inches long. Similar to C. dasyacanthus, from which it is distinguished by the fewer ribs, fewer and stouter spines, purple flowers, smaller fruit, and larger seed. This species is intermediate between the Pectinati and Decalophi.

"After Opuntia setispina, p. 294:

"O. PES CORVI, Le Conte, Mss. : articulis parvis teretiusculis; pulvillis subconfertis setas paucas breves graciles flavidulas gerentibus plerisque armatis; aculeis binis ternisve gracilibus sæpe basi compressis tortisque ; flore flavo minore.

"Sandy coast of Georgia, Major Le Conte, and Florida, Dr. Chapman. Joints not much over an inch long, and half as thick. Spines 1-1 inches long, straight and slender. Flower 1 inches in diameter. Ovary only with 5 areola; stigmas 5.- In the shape of the joints this curious little species resembles O. fragilis, but in other respects it seems intermediate between O. vulgaris and O. tenuispina."

Professor Agassiz addressed the Academy on the general characters of Orders in the classification of the animal kingdom. Orders, he said, are natural groups characterized by complication of structure. There are groups, however, constituting orders, which do not come under this definition; hence he concludes that the different classes of the animal kingdom do not all admit of the same divisions. Professor Agassiz illustrated his views by the different orders of Echinoderms. In conclusion, he remarked, that orders are of different kinds, some synthetic, some prophetic, others graduated. After nomination by the Council,

Laurens P. Hickok, D. D., President of Union College, Schenectady, was elected an Associate Fellow in the Section of Philosophy and Jurisprudence.

Dr. George B. Wood and Dr. Isaac Hays, both of Philadelphia, were elected Associate Fellows in the Section of Medicine and Surgery.

John Stuart Mill, of London, was elected a Foreign Honorary Member in the Section of Political Economy and History. Manuel J. Johnson, Director of the Radcliffe Observatory, Oxford, was elected a Foreign Honorary Member in the Section of Practical Astronomy and Geodesy.

Four hundred and thirty-fourth meeting.

January 13, 1857. MONTHLY MEETING.

The Academy met at the house of the Hon. Robert C. Winthrop. The President in the chair.

The Corresponding Secretary read letters from Dr. George B. Wood, Dr. Isaac Hays, and Laurens P. Hickok, accepting Fellowship; from the Essex Institute, the American Antiquarian Society, the Royal Institution of Great Britain, the Society of Arts, Manufactures, and Commerce, Professor Faraday, and Sir Charles Babbage, acknowledging the receipt of the Academy's publications; from the American Oriental Society, acknowledging the same, and presenting Vol. V. No. 2 of its own Journal; and from the Société Nationale d'Agriculture, &c. de Lyon, and the Académie Nationale des Sciences, &c. de Lyon, presenting their publications.

Professor Agassiz reminded the Academy of the recent death of a distinguished associate in the following words:

"It is the first time we meet since the death of the Hon. Francis C. Gray, one of our fellow-members. Though there are others longer acquainted with Mr. Gray than myself, who are better qualified to speak of his general merits, allow me to take this opportunity to make known to you some incidents relating to the last objects upon which his mind was seriously engaged. I have not had the happiness of knowing Mr. Gray intimately for many years; but for the last two years peculiar circumstances, which are among the most fortunate of my life, have brought me gradually nearer to him, and enabled me to become more closely acquainted with his extensive attainments, and the great powers of his vigorous and clear intellect, and to appreciate fully the kindness of his feelings, and his unbounded benevolence.

"There is hardly any field of intellectual activity which did not

engage at some time or other his inquisitive mind. But among the many objects to which he has turned his attention, there is one topic which particularly deserves to be noticed on an occasion like this, when the members of the Academy must feel that they have sustained a severe loss by his departure. Taking, as was his habit in everything else, a broad view also of the events of the day, he had satisfied himself that there is no field in which young men of ability could seek for a better opportunity of doing good service to their country, than in the pursuit of science, literature, and the arts. And this subject was one to which he returned constantly in conversation for the whole past year. Early in 1856, he was invited by the Regents of the University of the State of New York to deliver an address in Albany, on the occasion of the inauguration of the Geological Hall. His sickness unfortunately prevented him from attending the celebration. The subject he had selected for the occasion was that of his constant thoughts. He hoped to make an impression upon the community by an earnest appeal to the rising generation in favor of a deeper and more thorough cultivation of the learned vocations, and especially of science. No one among us was better prepared than he to set forth the great importance and the true dignity of such pursuits. He never tired of repeating that he considered intellectual and moral culture as the object worthiest of the highest ambition. It was not, he used to say, by prowess of arms, or by wealth, that nations could in future take a high standing among civilized communities, but by their devotion to, and their appreciation of, the higher interests of science, literature, and the arts. I need not say, that with him these were not idle words. I deem it my duty, as it is my pleasure, to refer to the great exertions he made, for a number of months in succession, to render possible the publication of my Contributions to the Natural History of the United States, and I truly lament that he did not live to see at least the first volume completed. But his great heart had higher aims than the personal success of a friend. He had conceived the plan of a great institution, devoted chiefly to the study of Natural History, in its widest ramifications, which should in course of time be for this country what the British Museum and the Jardin des Plantes are for England and France. He spoke repeatedly of the part he would take himself in fostering such a plan, and his will bears testimony to the importance which he attached to the establishment of such an institution. When he felt his strength failing him,

he lamented his inability to make an energetic appeal to his friends for such a purpose. He thought, if he could go only once more into the streets, he might effect something towards this end worthy of the country. The last time he spoke to me upon the subject, was to hint at the possibility and the means of carrying out this great plan. The emotion with which he spoke is still fresh in my memory, and will accompany me through life, as an evidence of the fervor with which a truly noble mind may be occupied with the highest interests of his fellow-men, in a moment when he feels himself already at the threshold of another world.

"I beg to offer the following resolution :

"Resolved, That the American Academy of Arts and Sciences have sustained, in the death of their late Associate, the Hon. Francis C. Gray, a loss not easily to be supplied. He was a man of vigorous mind, of large and liberal culture, of generous devotion to all good and noble objects, and a true friend."

The Hon. Josiah Quincy expressed his hearty concurrence with the sentiments expressed by Professor Agassiz, and referred to his own long acquaintance with Mr. Gray, in public and private, in terms most eulogistic and friendly. In conclusion, he moved that the resolution offered by Professor Agassiz be adopted, and that a copy of it, with the prefatory remarks, be printed in the public newspapers. The motion was seconded by Professor Treadwell, and adopted unanimously.

Mr. Sherwin read a paper on a new theory of parallel lines. Mr. Folsom laid upon the table two manuscript pamphlets, containing interesting memoranda of early meetings of the Academy, &c., which he had found among rubbish in the Athenæum. He regarded them as objects of much value, and, in conclusion, moved that they, with such other loose papers of the Academy as may be worth preserving, be suitably bound, and placed in the Library of the Academy, and that a committee of four be appointed to attend to the matter. It was voted accordingly, that Messrs. Folsom, Bowen, Felton, and the Librarian be a committee for this purpose.

Professor Horsford read the following paper, "On the Oleic Acid Series of Fatty Acids," by George C. Caldwell, B. S., Ph. D.

"The fatty acids obtained from the various animal and vegetable fats that occur in nature, it is known, are divided into two principal classes.

n

40

"The one class forms a part of the series of acids constituted according to the formula C, H, O1, while the other class forms the series with the formula C1 H1-2 0. The former series is by far the more completely developed, there failing but a few members, from formic acid, C2 H2 O, up to arachinic acid, C40 H0 O4. As we pass from one acid to another in this series, there is a gradual change in the properties of successive acids, corresponding to the change in the formula, a change which is exhibited more especially in the boiling point of those acids which can be distilled undecomposed, or in the melting points of those that cannot be.

"The other series is much less extensive, only the following members being yet known:

:

"Also, in this series we observe none of that perfect correspondence between the formulæ and properties of different acids in relation to one another.

"This latter series being at the present time rendered an object of more special interest by the discovery of a new member, we give here a short account of the series in general, in connection with the result of investigations on this new member, which its discoverer, Dr. A. Goessmann, afforded us an opportunity of making, in the labora tory of Professor Wöhler in Göttingen.

"The oleic acid, the principal and best-known member of this series, was discovered by Chevreul, and its characters were subsequently completely developed by Gottleib. It is a solid fat at low temperatures, but melts at 16° C., and then oxidizes very readily in the air, thereby becoming changed to a reddish-yellow oil. Two very characteristic properties of this acid are as follows:

-

"First. Under the influence of nitrous acid gas, it is transformed into an isomeric modification, not oxidizable in the air, and possessing a higher melting point than the oleic acid itself.