The operations, which succeed each other with this limited rapidity, are not incompatible with a partial attention to other subjects: just as in running or walking, we may have our feelings very strongly interested by the sight of surrounding objects without interrupting the train of voluntary motions, which seems thus to be so linked together in a continued chain, as to become almost involuntary. And we may certainly be saying a thing over as rapidly as possible to ourselves, and may at the same time be seeing, and hearing, and even reasoning, so as to keep up what amounts very nearly, though not completely, to a continuity of attention to several distinct trains of ideas: in the same manner as the nerves of involuntary action are notoriously employed in several distinct trains of concatenated muscular motions and vascular actions, and as the ear of a musician is able to follow and retain a dozen different melodies in harmony with each other at the same time. Dr. Darwin mentions an experiment which has a similar tendency to show the close connexion between thought and sensation. He says, that if we think intensely of a deep colour, for instance red, with the eyes closed, we shall see a tinge when we open them of the opposite colour, or green; just as if we had actually looked at a red colour instead of thinking of it. But I confess that I have never been able to satisfy myself completely of the success of the experiment. These very hasty observations appear to me to be in great measure original; and the results of such experiments are certainly more calculated to illustrate the nature and powers of the human mind, than the fanciful hypothesis of the fashionable [p310] craniologists, with all their measurements of the heads of murderers, are likely to become. ZMINIS. _London_, 20 _Oct._ 1827. POSTSCRIPT.—I find that some similar remarks have been made by the late Sir William Watson, in his Treatise on Time. He estimated, from some experiments made in company with his friend Herschel, the greatest possible velocity of sensation, such as to admit of about three hundred distinct impressions on the eye or the ear in a second. “It is true,” he observes, “that whoever attends to what passes in his imagination on particular occasions, will be struck at the apparent rapidity with which ideas appear to flow at times, and will be apt to suspect them far to exceed sensation in that respect. But it is probable that we are ourselves deceived in such cases.” P. 38. But there are no direct experiments to prove this opinion. On the other hand, a sound may be continuous, and yet consist of only about twenty vibrations, or still fewer, in a second. HIEROGLYPHICAL _Fragments, illustrative of Inscriptions preserved in the_ BRITISH MUSEUM, _with some remarks on_ Mr. CHAMPOLLION’s _opinions_. In _a Letter to the Cavaliere_ SAN QUINTINO. By a Correspondent. My dear Sir,