41 is a copy of the figure referred to in the quotation. 
"The next two examples, provided through the kindness of 
Dr. He. R. Seiwell of the Woods Hole Oceanographic Institution, 
are based on pressure recordings taken off Cuttyhunk Island, 
Massachusetts in 1946. They represent the pressure at a depth 
of 75 feet and reflect wave heights. The basic data are: 
Station 53-W 537X 
Date 15 Sept. 46 15 Sept. 46 
Time 0500 hours plus 0650 hours plus 
270 to 600 seconds 325 to 636 seconds 
Serial correlations 0O(1) 20 seconds 0(1) 16 seconds 
for lags of 
Length of run 331 seconds 301 seconds 
This type of data has been subjected to a few-constant fitting 
procedure based in part on quadratic autoregressive residuals 
as reported by Seiwell and Wadsworth --- and by Seiwell ---. 
"In this case also, the serial correlations have been 
analyzed as if they were serial products......The we values 
obtained by a simple equating method, show substantial negative 
values. Since true negative values are impossible this makes 
such equating methods entirely useless on such data. tie to." 
values, on the other hand, show a very reasonable behavior 
and, in particular are never negative by more than 0.004, which 
presumably results from accumulated errors and the use of ry 
instead of Qp° - 
"The upper frequency limit is 0.5 cycles/second for each 
record, since there is 1 sample/second. Thus for record 53-W 
we have a power density estimate every 0.025 cycles and for 
record 53-X every 0.03125 cycles. The results are plotted 
in [the] figure ..... We see that the general character of 
the results is the same, namely an unresolved peak near 0.075 
cycle/second and essentially no energy beyond 0.15 cycle/second. 
The peak frequency may have increased in record 53-X as compared 
with 53-W. 
"In order to study the nature of the peak near 0.075 
cycles/second, it would be natural to repeat the analysis so 
that the upper frequency limit would be at, say 0.125 cycles/ 
sec, which would be obtained by analyzing the record at 4 
second intervals and using lags of 0, 4, 8, ....., 80 seconds. 
Unfortunately this would lead to widely fluctuating results 
since there would then be only 82 points in the longer record, 
and there would be only 
82- + (20) 
ae eee 
20/2 
a7 
