expressed in digits of the ternary scale of notation, every digit be- ing either — 1, 0, or + 1. In this system, unity being, in multi- plication, only an index, the rules for multiplication and division must consist entirely in directions for the management of the signs of unity ; and it is on this principle that Mr. Fowler's machine is made to act. A short account is given of the principal parts of the machine, and of the mode in which they bring out the final results. It is necessary, however, in applying it to use, to have recourse to tables, both for converting the factors and reconverting the result ; operations which introduce both labour and risk of error.
1 1 . On the Minute Structure and Movements of Voluntary Mus- cles, in a letter addressed to R. B. Todd, M.D., F.R.S., &c. By William Bowman, Esq., Demonstrator of Anatomy in King's Col- lege, London, and Assistant Surgeon to King's College Hospital. Communicated by Dr. Todd.
The objects of the author, in this paper, are the following. — 1st. To confirm, under some modifications, the view taken of the primi- tive fasciculi of voluntary muscles being composed of a solid bundle of fibrillse. 2dly. To describe new parts entering into their com- position : and 3dly. To detail new observations on the mechanism of voluntary motion.
He first shows that the primitive fasciculi are not cylindrical, but polygonal threads ; their sides being more or less flattened where they are in contact with one another ; he next records, in a tabular form, the results of his examination of their size in the difi"erent di- visions of the animal kingdom. It appears that the largest are met with in fish ; they are smaller in reptiles, and their size continues to diminish in insects, in mammalia, and lastly, in birds, where they are the smallest of all. In aU these instances, however, an extensive range of size is observable, not only in different species, but in the same animal, and even in the same muscle. He then shows that all the fibrillse into which a primitive fasciculus may be split, are marked by alternate dark and light points, and that fibrillse of this description exist throughout the whole thickness of the fasci- culus ; that the apposition of the segments of contiguous fibrillse, so marked, must form transverse striae, and that such transverse striae do in fact exist throughout the whole interior of the fasciculus. He next inquires into the form of the segments composing the fibrillae, and shows that their longitudinal adhesion constitutes fihrillce, and their lateral adhesion discs, or plates, transverse to the length of the fasciculus ; each disc being, therefore, composed of a single segment from every one of the fibrillse. He shows that these discs always exist quite as unequivocally as the fibrillae, and gives several examples and figures of a natural cleavage of the fasciculus into such discs. It follows that the transverse striae are the edges, or focal sections of these discs. Several varieties in the striae are then detailed, and the fact noticed that in all animals there is frequently more or less diversity in the number of striae in a given space, not only on contiguous fasciculi, but also on the same fasciculus at different parts.
