EXPERIMENTS ON THE MEASUREMENT OF WATER. 181 
Cork, with the fine harbours of Waterford, Dungarven, Youghal, Cork, and 
Kinsale, and parts of the counties of Wexford, Waterford, and Cork. 
5th Province, South-West.—From Mizen Head to Kerry Head, or the 
mouth of the Shannon, embracing Bantry, Dingle, and Tralee Bays, the 
Kenmare River, and parts of the counties of Cork and Kerry. 
6th Province, West.—From Loop Head, county of Clare, to Erris Head, 
on Mullet Island, at the extreme north-west of Mayo, embracing Galway, 
Clare, and Blacksod Bays, the Isles of Arran, Clare, Achill, and Mullet, and 
parts of the counties of Clare, Galway, and Mayo. 
7th Province, North-west——From Erris Head to Horn Head, embracing 
Killala, Sligo, and Donegal Bays, and parts of the counties of Mayo, Sligo, 
and Donegal. 
“These seven Provinces might be easily subdivided, but I think this is not 
advisable; indeed, I am rather doubtful of the propriety of keeping either 
the 2nd or 5th Province: but still we find species peculiar to each of these 
localities, or at least occurring in them, and not generally found in the others : 
thus, Hc/inus lividus occurs iv Province 5, but hardly, if at all, in Province 4. 
I need hardly justify the utility of making these Provinces ; their convenience, 
when referring to geographical distribution, is obvious ; as by saying in which 
of these Provinces an animal occurs, we at once arrive at an idea of its dis- 
tribution in a much shorter manner than enumerating the counties it occurs 
in. I have hesitated to call the Provinces Boreal, Lusitanian, &c., thinking 
the time has not yet arrived for so doing. The Dredging Committees on 
the east, north, and south-west of Ireland will doubtless in time enable this 
to be done. I have only to hope this enumeration may be adopted, as it 
will render comparison so very easy.” 
On Experiments on the Measurement of Water by Triangular Notches 
in Weir Boards. By JAmMes Tuomson, 4.M., C.E., Professor of 
Civil Engineering, Queen’s College, Belfast. 
Tuer experiments proposed to be comprehended in the investigations to 
which the present interim Report relates, have for their object to determine 
the suitableness of triangular (or V-shaped) notches in vertical plates for 
the gauging of running water, instead of the rectangular notches in ordinary 
use. The ordinary rectangular notches, accurately experimented on as they 
have been, at great cost and with high scientific skill, in various countries, 
with the view of determining the necessary formulas and coefficients, for 
their application in practice, are for many purposes suitable and convenient. 
They are, however, but ill adapted for the measurement of very variable 
quantities of water, such as commonly occur to the engineer to be gauged 
in rivers and streams. If the rectangular notch is to be made wide enough 
to allow the water to pass in flood times, it must be so wide, that for long 
periods in moderately dry weather, the water flows so shallow over its crest 
that its indications cannot be relied on. To remove, in some degree, this 
objection, gauges for rivers or streams are sometimes formed in the best 
engineering practice, with a small rectangular notch cut down below the 
general level of the crest of alarge rectangular notch. If, now, instead of 
one depression being made for dry-weather use, in a crest wide enough for 
use in floods, we conceive of a large number of depressions extending so as 
to give to the crest the appearance of a set of steps of stairs, and if we 
