| Fig. 1. | a 1, a 2, &c. the tinfoil. | Fig. 2. | a, the intermediate slips passing over the edges of the glass and connecting plates, 1, 3, and 5. |
| b b b, plates of glass. | |||
| c, the intermediate slips connecting the plates 6, 4, and 2. | b, the slip which connects the upper sheet of foil with the 4th, &c. | ||
| d, the slips connecting 5, 3, 1, and the ground. |
In a battery of the ordinary form, it is evident that a much less surface is coated than in one of the above construction; in a battery of the common form, two feet long, one foot wide, and ten inches high, and containing 18 coated jars, there will be no more than 3500 square inches of coated surface, while in a battery of the same dimensions on the proposed construction, there will be no less than 8000 square inches covered with tinfoil, allowing the sheet of glass and of foil to be ¼ inch thick.
When plate glass is employed for making this battery, the ring of glass exterior to the tinfoil may be covered with varnish, and then the next plate laid over it; the tinfoil will then be shut out for ever from the access of moisture, and the insulation will remain perfect. This form of the Electrical Battery is very portable, may be packed in a case with the machine, and indeed a powerful battery occupies no greater space than a quarto volume. It is cheap and easily constructed.
Art. XV. Chemical Examination of the Berries of the Myrica Cerifera, or Wax Myrtle.
Art. XV. Chemical Examination of the Berries of the Myrica Cerifera, or Wax Myrtle, by J. F. Dana, M. D. Chemical Assistant in Harvard University, and Lecturer on Chemistry and Pharmacy in Dartmouth College.
(Communicated for this Journal.)
The myrtle wax of commerce has been examined by Dr. Bostock and by M. Cadet; the entire berry not having been made the subject of analysis, I have been induced to examine it, with a view to ascertain the proportion of wax.
I. Fifty grains of the most perfect berries were digested in repeated portions of warm alcohol, until the fluid appeared to exert no further action. The first portions of alcohol were tinged of a green colour, but the last portions remained colourless.