52 On the Winds of the Western Coast of the U. States. 
vicinity is indicated by the chart, the lines from xi to xv hours 
being crowded into the very small space of a few miles on the 
south side of Nantucket. 
T'o return to the more limited scale within which our induc — 
crease in the height of the tide im ascending. On the contrary, 
in Chesapeake bay, which widens and changes direction at 4 
right angle immediately from the entrance, the tides diminish in 
height as a general rule in going up the bay. 
The results of the heights of tides along the coast are very 
satisfactorily shown upon a model which is now before the A& 
sociation, for superintending the execution of which I am mm 
debted to Mr. Pourtales. The basis is a map of the Atlantic 
coast from Cape Florida to Cape Race, upon which the cotidal 
lines of the United States are traced. The tidal stations are — 
marked upon this, and rods cut to length and proportionate to 
the rise and fall of the tides at the several stations, are inserte¢ — 
in holes drilled at the station points. The steel rods refer to the 
heights at exterior stations and the brass rods to interior ones. 
Paper cut to the form of the general curve of heights, which 
has already been explained, and placed behind these rods, serves 
to show the generalizations with great distinctness. i 
I propose to call the bay between Cape Florida and Cape Hat — 
teras the Southern bay, that between Cape Hatteras and Nam — 
tucket the Middle bay, and that between Nantucket and Cape 
Sable the Eastern bay of the coast of the United States. 
The general figure of the coast line has of course heretofore 
attracted the attention of geographers. The connection with the 
heights of the tides could only satisfactorily be made out by sucha 
series of tidal observations as those embraced in the Coast Survey: _ 
Art. VIL—On the Winds of the Western Coast of the United 
States, from vations in connection with the U.S. Coast Sur — 
vey; by A. D. Bacus, Superintendent.—With a Plate. : 
{Communicated by authority of the Tr ican Asso” — 
' ciation for the conan "Selence peau ‘ 
THE observations, of which I propose at present to commun 
cate the results, were made in the year 1855, in connection with © 
the tidal observations on the Pacific coast, at three permanent 
stations, Astoria, San Francisco, and San Diego. The approx 
mate latitude and longitude of each of the stations is as follows: — 
Astoria, Oregon, —_—_at. 46° 11’ N.., long. 123° 49’ W. 
San Francisco, California, “ 87 48 | ete bs ee 
San Diego, ‘ * 82:40 S347 48 
