POTASH FROM KELP. 31 
which had been disseminated very soon after the old plants died. 
From October to December, 1917, enormous numbers of dead hold- 
fasts, with their stipes completely gone, were found on the beaches 
at Santa Barbara. These holdfasts were black, whereas the hold- 
fasts of a plant washed up by the waves normally is brown when it 
comes ashore, and it changes color but shghtly in drying. Moreover, 
black holdfasts, not differing in the least from those on shore, were 
seen coming in in the surf. Such holdfasts were found along the 
coast as far south as La Jolla, but nowhere in such numbers as at 
_ Santa Barbara. | 
In addition to the two just described other kelp beds near Santa 
Barbara practically disappeared. Puncturing and sinking may have 
occurred in these beds, but probably much of the destructive work 
was done by the bacterial disease, black rot, which destroys the kelp 
piecemeal, but very effectually, nevertheless. This disease, to be 
described presently, may have been responsible for the many dead 
holdfasts. 
None of the more exposed kelp beds farther south, or around the 
islands, sank, although those along the mainland became thin. Dur- 
ing the same warm weather the temperature of the water at La Jolla 
rose at one time to nearly 24° C., within 1° of the upper limit for 
kelp. It is therefore not unlikely that at some points along the 
sheltered Santa Barbara coast the surface water at least may have 
risen above the 25° C. limit of temperature. 
The water cooled noticeably in September (‘Table 2), and the kelp 
beds soon began to recover. Growth became more and more vigor- 
ous as the water cooled and winter weather came. By spring the 
kelp beds were yielding heavily (see Table 6 and fig. 11), and 
the supply was adequate. By midsummer the kelp was deteriorating, 
and by October there was a serious shortage, only half as much, 
approximately, some beds having practically disappeared.. This 
time, however, the cause of the disappearance was plain. 
TABLE 5.—Highest wind velocities attained at San Diego in successive months 
in 1917 and 1918, with direction at the time of highest velocity, in miles per 
hour, taken as an index of stormy weather. 
2 ete See eS Z 
sda ~ 1892-1918 . | 1892-1918 
Month. is page por Month. 1917 1918) ee 
| 
— = = ate | — ca a | Ft _ = —_<<$$—$ 
Pt nee ae 33S 33 S. 28 WUryt ace eto 21NW.; 20 NW.) 20 
February: 22.22 -: 34S. 348. 304 j/ PAM PUSE Ly ieee: LIV he 19.6 
Mare <= at oy. ZANW.! 24 NW: 30.3 || September.-........ 27 NW.) 22S. | 21.2 
1.50) 7) ie de eee 43 8. 43S. 25 Wctover eo ft. 26NW.. 22S. | 21.1 
Mage osu loos! . 248. 24S. 25.1 |; November. --...... 25) S..5- fz, NWI 24.3 
Ete E'S | 2ONW. 30S. 20.1.) December.) 5.22227 ITNW.) 35 W. | 26 
ee 2 = a SS a a ee ae : a z ~ — — —. ee 
The winds had been practically the same as in 1917. (See Tables 
3 and 4.) The water, in July and August, had risen to almost as 
high a temperature as in 1917 and had remained so high that in 
October it was warmer than in the same month of the preceding 
year. In addition to lack of air and water circulation, and to the 
high temperatures, the weather was unusually cloudy. Early storms 
in September and October (Table 5) also, did great damage to 
some of the beds. 
