178 ANNUAL OF SCIENTIFIC DISCOVERT. 



EXPANSION OF ICE. 



Tho Rev. Frederic Gardiner contributed a paper to the " Amer- 

 ican Journal of Science," vol. 40, 1805, on tlie formation of ice in 

 the Kennebec River, in the town of Gardini-r, Me., in Fehrnary 

 and Marcli, 1805. Tlie river here is altout 7(H) feet wide; tlie 

 water is entirely fresh for many miles below, and the averaj^e ebb 

 and How of the tide is 5 feet; tiie depth of the water varies, ac- 

 cording to the locality and the state of tlu; tide, from 17 to 2o feet. 

 In the course of the winter the ice is always observed to crowcT 

 ashore, crumplinfj up in ridges on the Hats and near the edge of 

 the channel. Tiiis process was well ad\'aneed when his observa- 

 tions were begun, Feb. 6. A row of stakes was jjlanted in the 

 lee, by boring holes through to tiie water, at distances of about 

 100 feet apart, avoiding a very near ajjproach to the shore. The 

 distance between the eastern and western stakes was 500 feet. 

 !Mareh 18, the eastenmiost stake had advanced to the eastward 

 125 inches ; a stake 200 feet west of tliis had not sensibly changed 

 its position ; the westernmost stake had moved to the westward 

 12^ feet. There was thus a total expansion of the ice of 13 feet 

 2| inches in a breadtii of .000 feet, — 2.040 per cent., nearly, in 40 

 days. Of course this motion is entirely independent of the action 

 of gravity, and is possibly due to variations in the temperature of 

 the air, that of the water having been nearly constant. The tem- 

 perature ol)scrved at his house, 120 feet from the river, was as 

 follows : From Feb. 6 to 28 inclusive, mean temperature 22.37° 

 Fahr. ; mean of extreme heat each day 32° ; mean of extreme 

 cold 12.74°; extreme heat 4.5°; extreme cold 17°. March 1 to 

 18 inclusive, mean temperature 33.138°; mean of extreme heat 

 41.33° ; of extreme cold 24.944° ; extreme heat .50° ; extreme cold 

 7°. These temperatures are each that of the shade. His observa- 

 tions show that the ice expands witiiout reference to the tempei-a- 

 ture of the water, and that the temperature of the ice itself varies 

 considerably, its changes having little reference to the water be- 

 low. It also appears that the rays of the sun at these depths are 

 absorbed largely by an enclosed object, even of a light color. In 

 the uniform temperature of the water, at various dejiths, there is 

 evidence that the sudden disintegration of the ice, and its disap- 

 pearance, is not in this instance due to the action of the water. 

 This occurs constantly on the large ponds in the neighborhood, 

 but rarely on the river. It never takes place until the "snow 

 ice " is entirely melted, and is believed to be due to the action of 

 the sun. 



AFRICAN TELEGRAPH. 



It has been stated in a repoi-t to the British Association, that the 

 negro had never shown ingenuity enough to invent letters, sym- 

 bolic or phonetic. That this is untrue is shown by the "Elliem- 

 bic" or African telegraph, au instrument which has been in exist- 

 ence for time immemorial to the oldest inhabitant in the Came- 

 roons country, on the Avest coast of Africa. By the sounds produced 

 on strildng tiiis instrument, the natives carry on conversation with 



