_ imper 
of the Coast of the United States on the Gulf of Mexico. 11 
Groups A and B, composed of Cape Florida, Indian Key, and 
Key West, and of Indian Key, Key West and Tortugas, espe- 
cially the first, give plausible results and the computed establish- 
ments vary but 1°5 mins. at the greatest, from the observed. I 
have not been able to form any satisfactory connection between 
these groups and those on the western coast of the peninsula. 
The next group which gives a tolerable result is Egmont Key, 
Cedar Keys, and St. Marks. In this the direction of the cotidal 
line, the velocity and the establishments are satisfactory. ‘The 
establishment of St. George’s station is irregular and is very 
probably erroneous. The semi-diurnal wave is composed of two 
very small ones, and it has been necessary to reconcile the dis- 
crepancies which they presented, sometimes one being the govern- 
ing tide and sometimes the other. 
Group D, composed of Fort Morgan, Cat Island, and South 
West Pass is the next which gives a good result. E, com 
of Isle Derniére, Caleasieu and Bolivar Point, and F, of all the 
stations from South West Pass to Brazos Santiago except Aran- 
Sas, give good results as to direction and velocity. 
The computed establishments as in the case of the diurnal 
wave present considerable discrepancies from the observed. The 
least difference is 8™5 and the greatest 67™, 1ese groups are 
marked upon the chart No. 6 and the cotidal hour next before 
and after the mean cotidal hour of the groups. 
0, and 21 occur in the same space, "between South West Pass 
and the Brazos Santiago in the semi-diurnal tide. T shall con- 
tinue to collect. observations bearing upon the facts discussd in 
this paper and to have them worked up, and so as to amend 
