PROF. YOUNG, of Dartmouth College, observed on the 7th of September, and has recorded in the Boston Journal of Chemistry, what appears to have been a very sudden and violent explosion on the surface of the sun. He was examining an enormous protuberance or hydrogen cloud on the sun’s eastern limb, which, by his calculation, was 100,000 miles long by 54,000 high, floating at a height of 15,000 miles above the surface, and sending down to the sun pillars of its own substance like a vast banyan grove. Being called away from the telescope a few moments, he was astonished, on returning, to find that the whole cloud had been blown into flying filaments, which rose, as he gazed with a greater rapidity than had ever been before observed in this substance, to a height of more than 200,000 miles from the solar surface. Hydrogen, in this state, has never before been recorded as rising so high. As these broken filaments streamed upward, they melted away like wisps of filmy cloud. Meanwhile, a little cap or knob which has been noticed near the substance of the sun developed wonderfully into a pyramid of flame 50,000 mile in height; there its summit was drawn out into long filaments and threads, which were most curiously rolled backward and downward like the volutes of an Ionic capital, and finally it faded away, and at half past two (the first change was observed at five minutes to one), had vanished like the other. A fine aurora borealis occurred during the evening which succeeded.