554 
Proceedings of the Royal Irish Academy, 
LIII. — jN'ote on additional Instances op the Tidal Floatation of 
Sand. By Henry Hennesst, F. R. S. 
[Read December 8, 1873]. 
I VENTURE to communicate to the Academy a few additional instances 
of the curious phenomenon which I have described in detail, and 
explained as an illustration of known physical laws in my paper read 
April 10, 1871, which is printed in the Proceedings, ante, p. 153. 
On June 11, 1872, I observed fragments of shells with small sand 
at Merrion, about 1 o'clock p. m., floating with the rising tide. The 
day was calm and the water smooth, otherwise the conditions were 
not very favourable. I present specimens of some of the flat fragments 
of shells which were seen thus floating. They readily sink on being 
completely wetted. 
On May 11, 1873, at 9 o'clock, a. m., I observed the tide^ rising 
rapidly on the strand near Sandymount, and carrying with it broad 
patches of sand mingled with a few small flat pebbles, broken flakes of 
shells, and bits of slate. 
The morning was bright, warm, and very calm, thus presenting all 
the conditions favourable to the phenomenon. 
I have been informed by Mr. G. H. Kinahan, M. E,. I. A., of the 
Geological Survey, that he has noticed the floating of sand with the 
rising tide at Killery bay, on our west coast. Although there was 
surf outside the bay at the time, the water where the sand was seen 
floating was calm. 
The same observer informed me that he noticed a similar pheno- 
menon at Manin bay and at Ballyconeely bay. He saw sand carried 
far up the estuary close by Owney Island, near Clifden. 
These instances, in addition to those already mentioned in the 
Proceedings, prove that the floatation of sand by the tide is not a rare 
and accidental phenomenon, but probably one of frequent occurrence, 
and therefore, of geological and geographical interest. 
See Proceedings, loc. cit, also for April 8, 1872, ante, p. 252. 
