3b Mr. W, R. Biit o/j the Great Symmetrical 



A. B. 



Protocarbonate of manganese . 74t'55 TO-Q* 



Carbonate of lime a trace 2*43 



Protocarbonate of iron .... 1501 11 '04 



Chiy and sand '33 '37 



Organic matter, moisture and loss 10" 11 622 



100-00 100-00 

 The carbonate of manganese is known to be one of the 

 rarest forms in which that metal occurs ; and so far as I am 

 aware, it has been hitherto found only in a compact and cry- 

 stallized form. The condition of the substance now described 

 may therefore possibly be quite new to science ; but certainly 

 it has not been found constituting a kind of marly deposit 

 spread extensively under bog, nor is it known at all as an Irish 

 mineral. 



It is highly probable that the study of the action lo which 

 this material is subjected under its native condition, may 

 throw some light on the theory of the impregnating and ce- 

 menting of rocks by the peroxide, and mdeed perhaps to the 

 mode of generation of the native earthy peroxides of manga- 

 nese. I shall however not at present enter on that question, 

 but merely indicate to philosophical geologists the fact of this 

 mineral certainly influencing, by its chemical actions, the 

 rocky masses with which it is associated. 



Museum of Irish Industry, 

 51 Steplien's Green, Dublin. 



VI. On the Great Symmetrical Barometric Wave, November 

 1847, a}i(/ other important undulations. By William Rad- 



CLIFF BiRT*. 



JN the engraving illustrating this article (p. 45), fig. 2 indi- 

 cates thii Jbrm of the great symmetrical wave of November, 

 as it passed London in the present autumn. It is placed under 

 the great wave of November 1846, fig. 1, for the purpose of 

 exhibiting the points of similarity and difference. The most 

 casual glance of the eye will detect a considerable similarity 

 with a much greater range in 1847; also a larger development 

 of the individual waves. 



In 1846 the wave commenced on the 2nd, culminated on 

 the 9th, and terminated on the 17th. 



In 1847 the wave commenced on the 8th, culminated on the 

 Hth, and terminated on the 21st. 



Previous to offering some remarks on the last return of the 



great symmetrical wave, it will be desirable to solicit the 



attention of the reader to the tj/pe of the barometric oscillations 



during the middle poition of November, as ascertained in 



• Coiuinunicatcd by llie Author. 



