s customary to dissolve out
the mineral matter from white filtering paper by washing in dilute
hydrochloric and hydrofluoric acids. Sixth, the use of infusorial
silica for drying purposes. Being very porous, it will absorb five
times its own volume of water. If a filter paper, holding a wet
precipitate, be placed upon a layer of this earth, it will become
quite dry in a very short space of time. Mr. Austen also remarked that
substances retain their heat for several days when placed in cork
boxes. To keep a substance air-tight, it may be placed in a flask, the
neck painted with a solution of india rubber in chloroform, and a
plate of glass laid upon it. The solvent quickly evaporates, leaving a
delicate film of rubber, which holds the glass tightly in place.

The next meeting of the Chemical Section will be held February 12; of
the Mineralogical Section, February 19.

* * * * *

ANNUAL REPORT OF THE PATENT OFFICE.

The annual report to Congress of the Commissioner of Patents, for the
year 1876, has made its appearance.

The amount received on applications for patents, reissues, designs,
extensions, caveats, disclaimers, appeals, trade marks, labels,
copies, etc., was $757,987.65. The amount paid for salaries was
$425,930; other expenses, $226,612. Total payments, $652,542.

Number of applications for patents during the year 1876 21,425
Number of patents issued, including reissues and designs 15,595
Number of applications for extension of patents 2
Number of patents extended 3
Number of caveats filed during the year 2,697
Number of patents expired during the year 814
Number of patents allowed but not issued for want of final fee 3,353
Number of applications for registering of trade marks 1,081
Number of trade marks registered 959
Number of applications for registering of labels 650
Number of labels registered 402

Of the patents granted there were to--

Citizens of the United States 16,239
Subjects of Great Britain 511
Subjects of France 104
Subjects of other foreign governments