255 



Reports of the Pennsylvania Hospital for the Insane, &c. &c. By 

 Thomas S. Kirkbride, M.D. 8vo. Philadelphia, 1842.— From 

 the Author. 



A Discourse on the Death of General Washington, delivered 22d 

 Feb. 1800. By James Madison, D.D., &c. &c. 8vo. Phila- 

 delphia, 1831. — From Col. Hugh Mercer, of Virginia. 



Biographical Sketches of Gen. Hugb Mercer. — From the same. 



Philadelphia Directory, for 1841. — From Mr. Du Ponceau. 



Report from the Commissioner of Patents, showing the Operations 

 of the Patent Office, for 1842. — From Hon. J. R. Ingersoll. 



Congressional Documents: Military Posts, U. S., 1842. — From the 

 same. 



Prof. Bache referred to the formula of Prof. Apjohn, for 

 connecting the indications of the wet and dry bulb thermome- 

 ter with the dew-point, to show that its results might approxi- 

 mately be obtained by a sliding scale. 



He had constructed a scale for that purpose, in which, by making 

 separate divisions on the moveable part for different heights of the 

 barometer, and for temperatures above and below the freezing point, 

 the correction for the barometer was applied to the scale at the same 

 time that the dew-points above and below 32° were calculated. Mr. 

 Charles M'Euen had very much simplified the original proposal, and 

 Prof. Bache presented a sliding scale made by that gentleman; also 

 a circular turning scale, made according to a suggestion from Mr. 

 Lukens. Either scale is compact, and well adapted to use by obser- 

 vers who employ the wet bulb hygrometer. The approximation to 

 the numbers of the formula is close, the scale referring to a mean ten- 

 sion of vapour, between that at the evaporating point and dew-point, 

 while the corresponding term of the formula refers to the tension at 

 the evaporating point. Prof. Bache observed that in this discussion 

 it was necessary to assume that the formula itself is accurate. 



The Committee, appointed at the last meeting, to consider 

 the propriety of celebrating the hundredth anniversary of the 

 Society, reported, and submitted the following resolutions: — 



1. Resolved, That the American Philosophical Society will cele- 

 brate its centennial anniversary on the 25th of May next, and that 

 the members be specially summoned to attend on that day. 



2. Resolved, That a member of the Societv be selected to deliver 



