In measuring the enlarged photogram, B C was 1.87 inches, and B F, 0.07 inches; and as B C, the moon's semi-diameter on the 7th August, subtended an angle of 16'.29" = _a_. Let C F subtend an angle = _y_. 1.87 cot. _a_ ' " Then cotan. _y_ = ------------- = 17.54 = _y_. 1.94 16.29 = _a_. ' " Angle subtended by protuberance = 1.25. As Mr. Douglas had no one to help him in the dark room, there was some delay in getting No. III. plate; but whilst I was waiting for it, out shot an enormous flame from the bright point before mentioned. It shot out in about three seconds, not unlike a jet of gas from a coal in the grate and when it reached its greatest height (about one-third higher than that seen in photogram), it was blown off to the left, just like a flame acted on by a "blow-pipe," and came to a point. The part blown off was a bright white flame. (See lithograph.) Now, as my veracity, after Mr. De la Rue's letter, is doubtful, and as this phenomenon was not seen any where else besides Jefferson, I must substantiate the fact, Mr. Falconer, in his report to me, gives a drawing which is very similar to fig. No. 2; he says: "It assumed the shape of a red-hot crooked bar of iron; this, resting on the dazzling silvery coronal light, gave a strange and wonderous addition to the glorious scene we now beheld." But it was seen by all, and can be attested to by hundreds. When No. III. plate was ready, it had lost about one-third of its height, and its flame-like appearance. When No. III, plate is examined with a lens, all the lines that are shewn in fig. 3 are seen; and here I must make an extract from the report of Mr. Vail, who was observing the eclipse with an excellent 42-inch telescope, by Dolland, and who made his report long before I had examined the negatives with a lens. In speaking of this protuberance, he says: "Its outlines were perfectly well defined, and were not curves, but rather irregularly broken straight lines, and throughout it seemed marked by similar lines. It reminded me of the appearance one sometimes sees on the face of a cliff, where the rock is broken by horizontal and vertical lines." Now, it is most evident that Mr. Vail saw with a telescope what I photographed; and further, it would be impossible to have these delicate lines in a photogram, if there was any relative motion. Without entering into any discussion about what the protuberances are, or are not, I will only say that when the flame burnt out, the residium was a cinder, and which is shewn in photogram No. III.; this quickly tumbled down into a great heap, as seen in No. IV.