Botany — General Science. 1 89 



servations on the geographical -distribution of vegetables. Supplementary 

 to this memoir, is given an account of a new genus of plants of the natural 

 order liignoniacece, named Fieldia, in honour of Mr Baron Field, which 

 was discovered by Mr Cunningham in 1823, on the Blue Mountains, grow- 

 ing in shady forests which abound in the tree-ferns, • (Dicksonia Antarc- 

 tica, Labill. Cibotium, Kaulfuss.) 



Upon entering the dark shades of these forests, the traveller is forcibly 

 struck with the change of appearance of the timbers, from the Eucalypti 

 of the open country, to species of other genera not to be found in situa- 

 tions of dry exposure." 



IV. GENERAL SCIENCE. 



29. The waters of Salt Springs raised by Carburetted Hydrogen Gas, in 

 the State of Ohio. — In the western parts of the State of Ohio, a discharge of 

 carburetted hydrogen invariably accompanies all the salt water that has been 

 discovered. The gas is highly inflammable, and where there is a free dis- 

 charge of it, it will take fire on the surface of the water on the application 

 of a lighted stick, or the flash of a gun, and continue burning for days, 

 unless put out by a heavy shower or high wind. It is this discharge of gas 

 that brings the salt water from such vast depths in the bowels of the earth 

 to the surface ; and where salt water has been discovered, and the supply 

 of gas has failed, the water has immediately sunk in the well, and could 

 not, by any means used, be brought again to the top of the well. On the 

 little Muskingun, they have sunk two wells which are now more than 

 100 feet. One of them affords a strong and pure salt water, but not in 

 great quantity. The other discharges such vast quantities of petroleum, 

 and is subject to such tremendous explosions of gas, as to force out all the 

 water, and afford nothing but gas for several days, that they make but 

 little or no salt. The petroleum affords considerable profit, and is in 

 demand for lamps in work-shops — Professor Silliman's American Journal, 

 vol. x. p. 5. 



* The following note by Mr Cunningham upon this plant, will give some idea of 

 the curious vegetation of these regions. " This beautiful tree-fern, he says, whicr, 

 was originally discovered at the southern extremity of Van Diemen's Island, where 

 alone it had hitherto been observed, I found it also very general, in the dark forests 

 on the mountain named by the Aborigines Tomah, which is distant from the Hawkes- 

 bury Ford, at Richmond, about 20 miles. Some of the caudices or trunks of these 

 trees are thirty-five feet in bright, and measure from 12 to 16* inches in diameter 

 at the base. The stupendous size and extraordinary windings of the climbers with- 

 in these shades, particular of a Cistus with quinate leaves, whose supple stems mea- 

 sured from 20 to 24 inches in the circumference, the weight of the parasitical Orchi- 

 dece, Filices, &c. borne by them, as they swing to the violent winds of these elevat- 

 ed lands, adding to the grandeur and magnificent appearance of the tree-ferns, 

 failed not to picture to me, and impress me with that exuberance of tropical scene- 

 ry, which, in New South Wales, is occasionally to be observed in the higher lati- 

 tudes, (particularly at the Five Islands.) 



