Halket .— The Effect of Salt on the Growth of Salicornia . 147 
of the Salicornias in the pans treated with the 1 % solution of Tidman’s sea 
salt and with distilled water were measured again on June 25, when it was 
found that the difference of growth was maintained. The average height 
of the plants was 39-2 mm. in the first case, while it was 29.9 mm. in the 
second. 
The effect of salt on the growth of Glyceria maritima was also noted. 
In the pans treated with the higher percentages of salt, 3 %, 4 %, and 5 %, it 
was found that after a time the plants turned yellow and finally died, while 
growth was greatest in the pans treated with water containing no salt. On 
June 25 the average height of the grass in each pan was obtained, and the 
decrease in growth according to the increase in salinity is shown in Diagram 2. 
Here the dotted lines represent the height of the Glyceria in the four sets 
of pans, A, B, c, and D, while the unbroken line gives the average height of 
the Glyceria . 
It seemed to follow from these experiments that Salicornia ramosissima 
grew best when it was treated with a somewhat dilute solution of Tidman’s 
sea salt (1 %), a considerably weaker solution than that of sea water. The 
other two salt marsh plants experimented with were less tolerant of salt. 
Stiaeda maritima grew as well without salt as with it, while Glyceria 
maritima flourished much better in its absence. The fact that the plants 
were grown in soil made it somewhat difficult to be certain what was the 
actual salinity of the water available for the plant. When the experiments 
were begun, as the pans were comparatively small, it was thought that by 
immersing them for some time in the various solutions the excess of salt in 
the soil would be washed out, and that the salinity of the water in the soil 
would be approximately the same as that of the solution in which the pans 
were immersed. It was obvious that there was a certain variability in this 
salinity as, between the periods of immersion, water was lost from the soil 
by evaporation and through the transpiration of the plants. In order to 
ascertain the amount of this variation estimations were made of the salinity 
of the soil water in certain of the sods before and after immersion. The 
salinity was obtained by estimating the amount of water in the soil and the 
amount of chloride present, and then calculating the amount of salt in 
100 c.c. of water, the chlorides being calculated as sodium chloride. 
Portions of soil were taken from one set of pans on June 5, just before the 
pans were immersed in the various solutions. The period of immersion 
lasted two hours and a half, then the pans were allowed to drain ; a second 
lot of samples was taken on the morning of June 6. 
The results of these analyses brought out the fact that not only was 
there a considerable variation in the salinity of the water of the soil in each 
pan, but also that this salinity was much greater than that of the solutions 
with which they were watered. It was found that the excess of salt was 
not washed out during the periods of immersion, but accumulated in the 
h 2 
