and contained three grammes of the oxide. Although the results of the analysis indicate that the temperature of the air-bath was too low, they also show, by comparison with the results obtained in operating with strongly ignited oxide at about the same temperature of the airbath (see p. 92), that the brown oxide is decidedly preferable in respect to the temperature required. This was also shown by the appearance of the oxide after combustion, the newly formed chloride being confined, in the case of the brown oxide, to a much shorter space. Results of the Analysis.-0.1640 gramme of chloride of amyl gave 0.3504 of carbonic acid, 0.1562 of water, and 0.1884 of chloride of silver.

Analysis 4.- Used the same preparation of oxide of copper as in Analysis 3, viz. the brown oxide. Temperature of the air-bath reached 170°. Slight carbonization occurred just at the close of the combustion, from extending the heat backward too soon, under a wrong impression that the substance was all burnt. Were it not for this circumstance, it is believed that this would have been a good analysis, although the temperature of the air-bath was kept so low. That a higher temperature of the bath is desirable, however, is shown by the fact that the chloride of copper appeared diffused over a space of 21 inches. The length of the column of mixed asbestos and oxide of copper was only four inches in this experiment, containing but one gramme of the oxide.

Results of the Analysis.— 0.1568 gramme of chloride of amyl gave 0.3195 of carbonic acid, and 0.1522 of water.

Analysis 5. The oxide of copper employed was of the same preparation as that of Analyses 3 and 4. The temperature of the air-bath, however, was considerably higher, ranging from 240° to 247°. The

mixture of asbestos and oxide of copper occupied a space of five inches in length, but contained only two grammes of the oxide. At the close of the combustion there was no appearance of chloride of copper, except at the back end of the column, a space of an inch in length.

Results of the Analysis. -0.1631 gramme of chloride of amyl gave 0.3383 of carbonic acid, 0.1557 of water, and 0.2157 of chloride of silver.

It can hardly have escaped observation, that the quantity of oxide of copper or oxide of zinc required to absorb the chlorine by this process is extremely small, in consequence of its being uniformly diffused through a large mass of asbestos; hence it is obvious that but little of a solvent is needed to extract the chloride. In this respect the new process bears a striking contrast to the old one, which involves the use of a large quantity of lime, necessitating a corresponding quantity of acid, and introducing disagreeable manipulation, which tend to increase the liability to error.

I have not yet tried the process recently described by Carius,* as the difficulty which I had found in obtaining tubes that would bear the pressure incident to his process for the determination of sulphur gave no encouragement of better success in the use of his process for the determination of chlorine, which is performed in a similar manner, although more complicated.

The advantage which my process affords, of being able to determine the three elements carbon, hydrogen, and chlorine at a single combustion, without the introduction of any difficult or hazardous manipulation, induces the belief that it will be found preferable to any other that has been devised.

* Annalen der Chimie und Pharmacie.

Five hundred and sixty-second Meeting.

February 13, 1866.- MONTHLY MEETING.

The VICE-PRESIDENT in the chair.

The Corresponding Secretary read letters relative to exchanges.

Professor Washburn read a paper on the nature of the testimony of experts in courts of law; and he suggested that a legislative remedy might be found for the abuses to which the employment of expert witnesses by the parties in a suit frequently leads. A discussion of the questions raised in this paper then followed, in which the following gentlemen took part: Dr. C. T. Jackson, Professor H. R. Storer, Professor C. W. Eliot, Professor Parsons, and Dr. J. Bigelow.

Five hundred and sixty-third Meeting.

March 6, 1866.

The PRESIDENT in the chair.

SPECIAL MEETING.

The President called the attention of the Academy to the recent decease of the Right Rev. John B. Fitzpatrick, of the Resident Fellows.

Professor Washburn gave a recapitulation of his paper, read at the previous meeting, on the testimony of experts.

A discussion of this subject then followed, in which Professor Parker, Judge Bigelow, Mr. G. B. Emerson, Professor Bowen, Dr. Jarvis, Professor H. R. Storer, and Dr. Pickering took part.

On the motion of Professor H. R. Storer it was voted, That a committee be appointed to consider and report upon the subject of this discussion.

Pending the appointment of this committee the meeting adjourned.

Five hundred and sixty-fourth Meeting.
March 13, 1866.-ADJOURNED STATUTE MEETING.

The PRESIDENT in the chair.

The Corresponding Secretary read letters relative to the exchanges.

The President called the attention of the Academy to the recent decease of Mr. Jonathan P. Hall of Boston, of the Resident Fellows.

In accordance with the recommendation of the Finance Committee it was voted, That the additional sum of five hundred dollars be appropriated for paper and printing, to be expended by the Publication Committee during the current year.

A committee was appointed, in accordance with the vote of the previous meeting, to consider and report upon the subject of expert testimony in courts of law; viz. Chief Justice Bigelow, Professor Washburn, Professor H. R. Storer, Dr. Tyler, Professor Rogers, Professor Horsford, and Professor J. Wyman.

Five hundred and sixty-fifth Meeting.

April 10, 1866. MONTHLY MEETING.

The PRESIDENT in the chair.

The President called the attention of the Academy to the recent decease of Dr. Jared Sparks, of the Resident Fellows, of Dr. Charles Beck, Vice-President of the Academy, and of Dr. Whewell, of the Foreign Honorary Members.

The Secretary read a letter from the Treasurer of the Boston Athenæum to the Treasurer of the Academy, informing the Academy of the termination, on the 1st of July next, of the lease of the Academy's Hall, and notifying the Academy that the Trustees of the Athenæum propose to take possession of the Hall, after that date, for the use of the Athenæum.

On the motion of Mr. Bowditch the subject of this communication was referred to the Finance Committee, with powers to

make such arrangements with the Boston Athenæum as they may find feasible and deem expedient.

On the motion of Mr. Paine it was voted that application be made to the representatives of the late Jonathan P. Hall, for the meteorological observations made by him during the past nine years under the auspices of the Academy, and forming a sequel to the observations of Mr. Hall already published by the Academy.

Mr. Paine was appointed to make this application, and also to receive the apparatus furnished by the Academy for Mr. Hall's use.

Mr. C. M. Warren presented the following paper:

Note on an Improved Apparatus for the Determination of Vapor Densities by Gay-Lussac's Method; being a Modification of Bunsen's Apparatus for measuring Aqueous Vapor. By C. M. WARREN.

HAVING recently had occasion to employ the method of Gay-Lussac for taking vapor densities, I decided to follow the lead of Carius,* and substitute for this purpose the steam-bath apparatus, Fig. 1, devised by Bunsen,† for measuring the aqueous vapor formed in the analysis of gases, this seeming to me preferable to the apparatus described by Gay-Lussac. But when I came to use the apparatus which I had constructed, in conformity, as I supposed, with that of Bunsen, I found it defective in one particular. I allude to the fact that, in consequence of the accumulation of a stratum of water on the surface of the mercury in the cup i, Fig. 1, in which the measuring-tube, e, stands inverted, and also of an accumulation of water in dew-like drops on the sides of this cup, and on the sides of the cylinder c c, it was found impossible to make an accurate reading of the lower level of mercury.‡

As I was about to abandon the use of this apparatus and resort to that of Gay-Lussac, it occurred to me that the defect above mentioned

Annalen der Chemie und Pharmacie, CXIX. 316.

↑ Gasometrische Methode, p. 52; English edition, p. 47.

It is but just to remark, that my apparatus may have been defective in its proportions, as dimensions were not given in Bunsen's description, - for it does not appear that either Bunsen or Carius had any difficulty in making accurate observations with the apparatus that they employed.