400 Progress of Science. [July, 



exerted by the living heart of a cow will raise a column of fluid blood 

 nine feet high in a tube. The experiment cannot be made with the heart of a 

 living man, as death would be the result, but the height to which the blood will 

 spout when the artery of a man is cut is known ; also the height to which the 

 blood of a cow will spout under like conditions. By comparing the two 

 phenomena, the hydrostatical pressure exerted by the muscles of the heart of a 

 man has been approximately ascertained, as well as by another method. The 

 blood of a horse or cow will spout about 2^53 feet high when an artery is cut, 

 and the blood of a man 2'58 feet high; the blood would rise much 

 higher than this in tubes, because, when an artery is cut, Nature makes 

 an effort to close the orifice, to stop the bleeding. By various methods of 

 experimenting he had come to the conclusion that the muscular force con- 

 stantly exerted by the heart of a man is competent to raise between twenty 

 and twenty-one pounds one foot high in a minute of time. 



He also gave some little attention to the low musical note given by a 

 muscle when it contracts. When a muscle contracts it gives a low sound, 

 like the distant roar of cabs rattling along a rough street. There are several 

 ways of hearing this sound. One is, when lying in bed at night, to lay one ear 

 on the pillow, so that the pillow shall act as a sounding-board, and then 

 to clench the teeth. The contraction of the muscle which acts upon the jaw, 

 will then give the low roaring noise just mentioned. By means of tuning- 

 forks, he and others had determined that this musical sound corresponded to 

 35£ double vibrations per second. 



He said that when muscular fibre contracts it contracts to § of its length. 

 On measuring the muscular fibres of the heart,, he found that they were 

 so arranged that they could all contract to § of their length, and some 

 of them in so doing gave the interior of the heart a squeeze, which expressed 

 the last drop of blood from the pumping apparatus, so that no force was lost. 

 The human heart beats 57 times in a minute. He closed his lectures by 

 speaking of the perfection of the muscle which gives birth to the young of 

 animals, and with a few remarks to the effect that science was not opposed to 

 theology. 



CHEMICAL SCIENCE. 



Further particulars have now reached us as to the remarkable discovery by 

 Professor Seely of the solubility of metallic sodium and other metals in 

 ammonia. He prepares the ammonia gas in an iron-generator, to which is 

 attached a stout glass tube containing the metal to be subjected to the 

 ammonia. When sodium is subjected in this apparatus to the condensing 

 ammonia, before any ammonia is visibly condensed to the liquid state, it 

 gradually loses its lustre, becomes of a dark hue, and increases in bulk. The 

 solid then appears to become pasty, and at last there is only a homogeneous 

 mobile liquid. During the liquefaction, and for a little time after, the mass is 

 of a lustrous, copper-red hue ; the condensation of the ammonia and its 

 mingling with the liquid steadily goes on, the liquid is progressively diluted, 

 and passing through a variety of tints by reflected light, at last it becomes 

 plainly transparent and of a lively blue, as well by reflected as by transmitted 

 light ; the liquid now closely resembles a solution of aniline blue or other pure 

 blue dye-stuff. On reversing the process by cooling the ammonia generator, 

 the ammonia gradually evaporates out of the liquid, and the changes observed 

 during the condensation re-appear in the reverse order, till at last the sodium is 

 restored to its original bright metallic state. If the evaporation be conducted 

 slowly and quietly, the sodium is left in crystals of the forms seen in snow. The 

 formation of the transparent blue liquid and the restoration of the sodium are 

 steadily progressive, and the repeated and closest scrutiny of the process has 

 failed to reveal the slightest break or irregularity in its ' continuity. The in- 

 evitable conclusion from such facts is that the blue liquid is a simple solution 

 of sodium in ammonia, not at all complicated or modified by any definite 

 chemical action. The brilliant and varied colours exhibited in the experiment 

 may seem anomalous to some, when, in fact, a closer scrutiny of the case will 



