Polytechnic Association Proceedings. 845 



paehelia. 

 The inhabitants of Lee county, Va., were lately quite excited at 

 the simultaneous appearance of three rising suns, which some of 

 the more ignorant resrarded as an omen of comins; evil. The true sun 



CO o 



was surrounded by a beautiful colored halo; above this was another 

 partially developed halo, beneath whieh two mock suns were visi- 

 ble for a short time. The phenomena of colored halos are due to 

 the refraction of light by frozen particles floating in the atmosphere 

 at a great height, while the white or uncolored parhelic circles arise 

 from reflections. They are never seen unless the cirrus or cirro- 

 stratiis cloud intervenes between the sun and the observer 



TRANSFERRING CARBON PRINTS. 



Dr. H. Vogel of Berlin, gives, in The Philadelphia Photographer, 

 Swan's process for transferring carbon prints. A solution of gela- 

 tine one part, water eight parts and glycerine one-fourth of a part 

 is first made, in which the pictures are completely immersed along 

 with a piece of fine tissue paper. They are taken together out of 

 the solution, when tlM?y will adhere quite firmly to each other. 

 They are now dried, and with benzine it is easy to separate them 

 from the fine paper and paste them, or else paste the whole on card- 

 board and then separate. Dr. Vogel has also made some successful 

 attempts to transfer carbon prints to glass. For this purpose the 

 developed carbon print which still rests on the caoutchaouc paper, 

 is floated on a solution consisting of gelatine twelve parts, glycerine 

 three parts and water one hundred parts. Next on the Avarm plate 

 of glass a little of the above solution is poured; the picture is laid 

 on this, and the surplus of the gelatine is removed by pressure with 

 the fingers; when nearly dry the picture is brushed over in order 

 to tan it, with a solution of one part of chromate of iron in three 

 hundred parts of water; after this it is allowed to dry completely, 

 and is then by means of benzine, dissolved oif. On opal glass 

 these pictures are very pretty, particularly when the tissue is of a 

 brownish tone. These positive carbon prints on glass may become 

 important in the future, for it is easy to make from the positive 

 carbon print on glass a negative carbon print on glass also, and 

 thus we would have the means of supplying negatives and giving 

 the latter a permanence equal to the carbon print. 



UTILIZING WASTE COAL. 



Carefully conducted experiments have been made by a board of 

 .engineers, appointed by the Navy Department, to examine mto 



