182 Scientific Intelligence — Geology. 



fertility. A law was made, and is still in existence — though, un- 

 happily, like other laws in this island, very rarely or very imper- 

 fectly enforced — which made it penal to cut down a vinhatico or til, 

 if found near a fountain or on the banks of a river. The same effects 

 have been found to follow, in a greater or less degree, in all countries, 

 whether tropical or not, from the diminution of timber, whether 

 produced by the extension of cultivation or by other causes. — Dr 

 Mason and Mr Driver on Madeira, p. 234. 



7. Supposed Change of Climate i7i New Zealand. — Some of the 

 gold of California is beginning to find its way here, in exchange for 

 flour and timber, &c. Ready-made wooden houses, framed and 

 fitted, have been exported in considerable quantity to California, 

 and sell extremely well. Summer good, — crops abundant. It is 

 the opinion of nearly every one, that the climate has undergone 

 a great change since the occurrence of the violent earthquake, which 

 we experienced about eighteen months since, and a change for the 

 better. It is difficult at first to perceive any connection between 

 earthquakes and the weather ; but if electricity be supposed to be 

 a principal agent upon which earthquakes depend, the connection 

 will become more apparent. Be this, however, as it may, the fact is 

 certain, that since our earthquake the weather has been more genial 

 than it used to be. Another circumstance, however, which is a com- 

 mon matter of observation, is this, — that as the weather has become 

 more favourable to vegetation, it has been less so to health ; for 

 colds, influenzas, and slight fev^erish attacks, have been very preva- 

 lent of late, and much more frequent than what they formerly were. 

 During the first four or five months after I came here, it was exceed- 

 ingly rare to hear any one cough ; but this last summer nothing has 

 been more common. How fearful the cholera appears to have been 

 in England. No case, I believe, has been met with south of the 

 line ; the same thing is asserted of hydrophobia, but I do not know 

 with what truth. — Extract of a Letter from Dr D. Monro, New 

 Zealand. 



GEOLOGY. 



8. On the Results of the latest Researches explanatory of Car- 

 bonic Acid Exhalations. By G. Bischoff. — Bischoff found that car- 

 bonic acid was gradually separated from carbonate of lime, by silicic 

 acid with the co-operation of boiling water. This decomposition took 

 place, whether the silicic acid was in a soluble or insoluble condition ; 

 for even finely pulverized quartz decomposed the carbonate of lime, 

 the process, however, in that case being rather slower. Carbonated 

 oxydule of iron (Spatheisenstein) and the carbonate of magnesia be- 

 have in like manner ; the latter is decomposed even more easily and in 

 greater quantity than the carbonate of lime. The more facile de- 

 composition of carbonate of magnesia is shewn by the fact that 

 even boiling water by itself separates the carbonic acid from it, this 

 not being the case with the carbonated oxydule of iron. When, 

 therefore, either limestone, dolomite, or sparry iron occurs at a depth 



