1824.] Scientific Notices — Miscellaneous. 395 



transported from the sea to brackish water, where it also not 

 only lives, but improves in condition. 



" In the same manner the common cockle inhabits indiffer- 

 ently the muddy sand-banks near the sestuaries of rivers, which 

 are always soaked with fresh water, and those sandy or half 

 muddy shores where no such water is found. These are by no 

 means the whole of the instances which might be enumerated 

 in support of an opinion, of which the determination is so 

 important in the present state of geological science ; but as this 

 subject is too important to pass lightly over, and as the bounds 

 of this communication are already exceeded, I shall leave it to 

 those who may have the means and the inclination to examine it 

 in greater detail. I will only add, that the same considerations 

 will lead to similar doubts, where it has been attempted by 

 geologists to determine the nature of strata, as to their marine 

 or fresh water origin, by that of the remains of fishes found in 

 them." — (Journal of Science.) 



Miscellaneous. 



17. Fulminating Powders employed as Priming for Folding 



Pieces. 



The fulminating substances which have hitherto been em- 

 ployed for this purpose are four in number. 1. Fulminating sil- 

 ver; 2. Fulminating mercury; 3. A mixture of 100 parts of 

 chlorate of potash, 12 of sulphur, and 10 of charcoal; 4. A 

 mixture of 100 parts of chlorate of potash, 42 of nitre, 36 of 

 sulphur, and 14 of lycopodium. A variety of experiments on 

 their comparative advantages have been recently made in the 

 chemical laboratory in the University of Halle, by Lieut. P. W. 

 Schmidt. The following appear to be the most useful conclu- 

 sions at which he arrived. 



Fulminating mercury answers the purpose completely, but 

 he does not agree with Mr. Wright in considering it preferable 

 to fulminating silver. On this point, however, we feel disposed 

 to differ with Mr. S. By his own admission, it never fails to 

 inflame the gunpowder, and as it is not nearly so explosive as 

 fulminating silver, the risk attending its employment must be 

 proportionally less. The first mentioned mixture of chlorate of 

 potash is much preferable to either of the metallic fulminating 

 powders. It is not so liable to accidental explosion ; it leaves 

 behind it less acid matter, and does not corrode the iron so 

 rapidly ; and, contrary to what takes place with fulminating 

 mercury, its explosion is not followed by a deposition of mois- 

 ture. The facility and certainty of the explosion is the same in 

 both. 



The second mixture of chlorate of potash is not nearly so effi- 

 cacious as the first ; although this is chiefly a consecpuence of 

 the ordinary construction of the touch-hole. The method oi 



