June 3. Mr. Alison read a Part of a Memoir on the Life and Writings of the late Lord Woodhouselee.

A Paper by Mr. Cadell was read, "on the Lines that divide each semi-diurnal Arc into Six equal Parts.".

The intertropical parts of these lines for the climates of Greece and Italy constitute the hour lines on the antique sundials. Most of the writers on gnomonics have considered these lines as great circles; Clavius alone demonstrates that they are not great circles: and afterwards Montucla states, but without discussion, that they are curves of a peculiar nature. The celebrated and profound astronomer Delambre, having examined only the portions that occur on the Greek dials, controverts the opinion of Montucla.

The object of the Paper is to show that the curved surfaces, whose sections form these lines, are undulated, and of the nature of cones, the apex of one undulation being as much elevated above the equator as the apex of the next undulation is depressed below it.

To see the curvature of these lines it is sufficient to draw them on a globe; and the undulated cone is completed by conceiving the diameter of the sphere, which has described the first branch, to move progressively and continuously between the two parallels that touch the horizon, until the extremities of the diameter arrive at the points from which they sat out.

If it be proposed, for example, to draw on a globe the curve which contains the third and ninth antique hour line, that the figure may be more conveniently delineated, elevate the pole about 60°, and divide each semi-diurnal arc into two equal parts; a line drawn through the points of division is one bicrural branch of the curve; this branch terminates at a point in the greatest, always seen parallel; and to complete the curve the semi-diurnal arcs belonging to this point, considered as the mid-day point of a horizon, (forming the same angle with the equator as the first horizon, but on the other side), are to be divided into two equal parts, and the points of division being joined, a complete re-entering curve is formed on the surface of the sphere. A diameter of the sphere revolving,

with its extremity applied to this curve, forms the undulated conical surface; the portion of the diameter on the other side of the centre forms at the same time an opposite cone equal and similar.

The five undulated surfaces, each of which contains a pair of the antique hour lines, have each a different number of undulations.

At the same meeting a Paper was read by Dr. Jackson of St. Andrews, containing an elementary Demonstration of the Composition of Pressures.

June 17. Dr. Murray read a Paper entitled "A general Formula for the Analysis of Mineral Waters." The object of the paper was to give one method applicable to the analysis of all waters, instead of the diversity of methods hitherto employed.

Dr. Brewster laid before the Society a notice respecting some new discoveries on light. He found that water exists in nitrate of potash in the state of ice;-that the division of the pencil in doubly refracting crystals is produced by strata of different refractive powers; that one of the images becomes nebulous, as in the agate, when one set of the strata is broken. down and irregularly disseminated among the other strata; and that in certain crystals any one of the two images may be rendered nebulous, or may even be extinguished by a particu lar process. This notice contained also a general view of the distribution of the polarising influence in tubes and cylinders of glass.

Cinchona Bark.

[From the London Medical Repository, for August, 1816.] THE opinions of authors have very widely differed regarding the best species of this bark. The following is the sub stance of that of M. Hurtado, a Spanish physician, who has lately published an Essay on Intermittent and Remittent Fevers.*

* Annales Cliniques de Montpellier, tom. xxxix. p. 323.

The best cinchona is that of Loxa, a brown species, the bark of the cinchona condaminea of Humboldt and Bonpland. "It is distinguished, chemically, by its infusion decomposing tartar emetic, animal gelatin, gall-nuts, and sulphate of iron, independently of some other characters which are not found in the same degree in the other known species, and which are confirmed by the proportions and colours of the precipitates obtained." The best bark of this description is procured in the woods of Utizinga, Enatizinga, and Caxanuma. The second is the Kalysaya, or orange cinchona, the bark of the cinchona lancifolia of Mutis, the yellow bark of commerce; and when collected, dried, and preserved with care, is as valuable a febrifuge as the former kind. "It however," says Hurtado, "sometimes attacks the head, and occasions gripings;" but it produces excellent effects when mixed with the former species. The third kind is the cinchona commonly called huanuco, the bark of the C. oblongifolia of Mutis, the red bark of the shops. The Spanish physicians have very little esteem for this bark.

M. Hurtado assents with the opinion of the majority of authors, that cinchona is most efficacious when administered in the form of fine powder; and next to that he recommends an infusion obtained by the simple maceration of the bark in

warm water.

M. Laubert has extracted from cinchona bark, by means of sulphuric ether, a greenish substance, which possesses many of the characteristics of bird-lime, and an essential oil of a very peculiar nature. In the superior kinds of cinchona this oil has the aroma of benzoin; in the common kinds, the colour is less agreeable, and the oily substance appears more allied to the resins than the volatile oils.

VOL. VI.

4 A

No. 24.

Extract from a letter on the best mode of softening Adhesive Straps.

[From the Edinburgh Medical and Surgical Journal, for July, 1815.]

THE Custom of carrying up chafing-dishes with cinders in them, still in use in some hospitals, is highly objectionable, both on account of the offensive nature of the vapour to the patients, and of their answering their purpose imperfectly. All that is necessary, and what is used in most English hospitals, is a large tinned case, from a foot to a foot and a half in diameter, filled with hot water. The back of the strap is applied around the circumference of the case, and is retained there till the plaster be as much softened as you wish. The greatest advantage of this method of warming the plaster is, that it produces an equable heat, and at the same instant of time; of great consequence, particularly after amputations.

DISPENSARIES.

Two more Dispensaries have been established; one in the Northern Liberties and the other in the District of Southwark. They are formed on the same plan as the Philadelphia Dispensary. The increase and extension of population have made these additional institutions necessary, in order to afford suitable medical relief to the indigent part of the community.

UNIVERSITY OF PENNSYLVANIA.

THE Trustees have, in addition to those already established in the Seminary, instituted a Faculty denominated "The Faculty of Natural Science," to consist for the present, of the following Professorships:

1. A Professorship of Botany and Horticulture.

2. A Professorship of Natural History, including Geology, Zoology, and Comparative Anatomy.

3. A Professorship of Mineralogy and Chemistry, as ap

plied to Agriculture and the Arts.

4. A Professor of Natural Philosophy.

UNIVERSITY OF PENNSYLVANIA.

THE Medical Lectures will commence on the first Monday in November.

Practice of Medicine, &c. Dr. Chapman.

JUDGE COOPER proposes to commence a Course of Chemical Lectures early in November. Due notice of time and place will be given.

LECTURES ON NATURAL HISTORY.

DR. CALDWELL will deliver, during the ensuing winter, a Course of Lectures on Natural History, Systematic and Philosophical, in which the several applications of the science to practical purposes will be particularly illustrated and enforced.

LECTURES ON NATURAL PHILOSOPHY,

BY DR. R. M. PATTERSON, M. D, Vice Provost, Professor of Natural Philosophy and Mathematics in the Collegiate Department, and Professor of Natural Philosophy in the Medical Department of the University of Pennsylvania.

Dr. Patterson intends to deliver a Course of Experimental Lectures on Natural Philosophy, during the ensuing winter, at the University, in Ninth-street. The Introductory Lecture