291 Dana on Wax. 



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 3600 square inches of coated surface, while 

 in a battery of the same dimensions on the proposed construc- 

 tion, there will be no less than 8000 square inches covered 

 with tinfoil, allowing the sheet of glass and of foil to be -} inch 

 thick. 



When plate glass is employed for making this battery, the 

 ring of glass exterior to the tinfoil may be covered with var- 

 nish, and then the next plate laid over it ; the tinfoil will then 

 be shut out for ever from the access of moisture, and the insu- 

 lation 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 

 JSIyrica 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.) 



JL HE 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 co- 

 lourless. 



II. The alcoholic solutions were poured into a small retort 

 of known weight ; the alcohol was carefully distilled off, and 

 the residuum dried ; deducting the weight of the retort, there 

 remained 1.8.6 grs. for the weight of the matter dissolved by 

 the alcohol. 



