472 



After this digression concerning varieties in the structure of the 

 heart, the author resumes his anatomy of the Squulus maximus, and 

 notices, among the peculiarities of the urinary passages, that there 

 is no proper urinary bladder, but a cavity comparatively small, that 

 is common to the urine and semen ; since both the vasa differentia 

 and ureters open into it at the distance of about four inches from 

 each other. 



The holders in the male Squalus have been noticed before ; but it 

 is now added, that in each holder is a canal, communicating with a 

 cavity between the skin and muscles of the abdomen, which is stated 

 to be eleven feet long and two wide. The surfaces of this cavity are 

 white, and extremely smooth ; and it contains a mucus more viscid 

 than any known animal secretion. 



Respecting the brain, it is remarked, that in the Squalus, as well 

 as in fish in general, the cerebrum is wanting, unless the part from 

 which the olfactory nerves arise be so called. 



The eye is very small for the size of the fish ; its largest diameter 

 being not more than three inches, and its shortest only one inch and 

 three quarters. 



The straight muscles that surround the eye are so much stronger 

 than would appear to the author requisite for moving so small a 

 sphere, that he thinks such strength can only be required in adjust- 

 ment of the eye for overcoming the stiffness of the sclerotic coat. 



Some further Observations on a new detonating Substance. In a Letter 

 from Sir Humphry Davy, LL.D. F.R.S. V.P.R.I. to the Right 

 Hon. Sir Joseph Banks, Bart. K.B. P.R.S. Read July 1, 1813. 

 [Phil. Trans. 1813, p. 242.] 



In a second letter which the author received from France, he is 

 informed that the detonating oil was there originally procured by 

 passing a mixture of chlorine and azote through aqueous solutions of 

 sulphate or muriate of ammonia ; but from the method of obtaining 

 it in this country, it is evident that the azote is unnecessary, as it is 

 obtained by exposure of any ammoniacal salt in solution to mere 

 chlorine. The oily fluid obtained by these means has the specific 

 gravity of 1*653. It is not congealed by cold, as the author had 

 formerly supposed, but remains fluid even when cooled by a mixture 

 of ice and muriate of lime. 



When kept in water, it gradually disappears, and the water be- 

 comes acid, having the taste and smell of weak nitro-muriatic acid. 



Concentrated muriatic acid decomposes it, disengaging chlorine, 

 and forming muriate of ammonia. 



In concentrated nitric acid it gives out azote. 



In dilute sulphuric acid it yields a mixture of azote and oxygen. 



In a strong solution of ammonia it detonates ; with a weak solu- 

 tion it yields azote. 



With the muriates of sulphur and of phosphorus, or with sulphu- 

 ret of carbon, it combines \vithout any violence. 



