864 Tkansactio.xs of the American Institute. 



Mr. Elliot thought that plates should be wrapped in paper, and 

 Kugo-ested that the paper should be made in water-proof with gutta- 

 percha boiled in linseed oil, or with some similar substance.. 



The Speed of Electricity Through Land "Wires. 

 According to observations made by G. Davidson, Astronomer, 

 United States Coast Survey, on the night of the 28th of February, 

 1869, at San Francisco, Cal., on a loop of telegraphic wire extending 

 thence to Cambridge, Mass., and returning to San Francisco, the 

 return signal being received on a chronograph near that receiving 

 the outgoing signal, it was found that the total interral of time 

 between the two signals amounted to eight-tenths of one second. 

 The entire wire was divided into eleven portions, of about 650 miles 

 each, and connected by repeaters, which sent from one portion to the 

 next a new electric current, having a greater speed than the original 

 one would have had it continued beyond the first reach of 650 miles. 

 It will be seen that the actual rate of transmission of each cur- 

 rent over 650 miles cannot be deduced from these data by dividing 

 the whole time by eleven, but we are assured that the practical speed 

 of a series of currents combined by relays is at the rate of 7,200 

 miles in 0.8 of a second. 



Changes in Female Animals. 



A correspondent of The American Naturalist states that a doe Avas 

 recently shot near Minneapolis, Minn., carrying a beautiful pair of 

 antlers, each Math four branches, and asks whether this is a new fact 

 in natural history or not? To which the editors reply that they 

 have never heard of a female deer assuming the characters of a male 

 before; but it is a well established fact that female birds living to 

 ©Id age often assume the plumage, and, to a certain extent, the 

 liabits of the male. In the museum of the Peabody Academy of 

 Science, at Salem, Mass., there is a pea-hen, that in the spring before 

 her death, at the age of nineteen years, changed her dull female 

 plumage for the bright plumage and full trail of the male bird. N. 

 Vickery, taxidermist, of Lynn, Mass., has the specimen mounted. 



After some discussion on the foregoing items, the next topic pre- 

 Bcnted Avas the 



Aurora Bt)REALis. 

 \)\'. A. AV. Hall read a portion of his paper on this subject, which 

 occupied nearly the rest of the evening, in which he ascribed these 

 phenomena to reflected solar light. 



