420 
FAIR LEY : BLOWING WELLS. 
rivers Wiske and Swale. Whether the currents proceed from any 
common cavity I do not venture to say. I have thought of 
placing- a large quantity of chlorine mixture or of free bromine in 
the disused well, and then sealing it up if possible so as not to 
leak during an out-current. Afterwards during such an out- 
current to test at Solberge for the free chlorine or bromine by 
means of iodide starch paper. The very large scale required for 
the experiment has hitherto deterred me from making it. 
Finally, the well at Ornhams, Boroughbridge, I only know 
from description from Mr. Paver Crow, of Ornhams Hall.* It is 
the well supplying his residence, and the currents observed are 
very striking and powerful. A workman one day who had 
occasion to descend the well shaft compared the roar and noise of 
the air current passing into the crevices of the rock to that of the 
water in a mill-race. The gearing in use at this well prevents its 
being closed for the purpose of attempting to measure the current. 
I have visited other wells in the neighbourhood of Solberge, 
and I have also analysed the waters. The latter are similar in 
character to that of the water from the blowing well, but no air 
currents exist. This fact bears on the idea that the currents may 
be due simply to the ramified fissures and porosity of the sand- 
stone. The extreme and immediate sensitiveness of the current 
to the slightest change of the barometer also tends to prove this 
supposition. 
The cavity is no doubt partly filled with water as indicated 
by the humidity of the out-current. 
Both in the neighbourhood of Ripon on the south, and near 
Darlington on the north, where the magnesian limestone comes 
near to the surface, it is extensively cavernous, and in many places 
the thin beds of overlying strata and sandstone have given way. 
In conclusion, I may suggest that similar phenomena no doubt 
occur elsewhere, and may be observed and reported now that 
* The water I have analysed and found it similar to that at Solberge. 
