My dear Father,

I hope you got a telegram about Convulvulus.² The thing I found on working out the measurements is that they told nothing at all. A day is too long a period—the bits of stem which are growing well grow at a tremendous rate for a couple of days & then almost stop so that I could never get any fair comparisons³

Today I am measuring 4 plants every 4 hrs 7 ^am—11—3—7 ^pm   I can measure to $\frac{1}{2}$ mm & I think with the rapid growth of 1 to 2$\frac{1}{2}$ mm pr hour I ought to make out. They have alternate 4 hr periods of light & dark— If I see no good results today I shall shut up.

Please give my love to Sara & say I hope it will not matter my coming later instead of when I ought to   I think I must go to Brittany by a boat leaving S’hampton Monday night⁴   I wonder if Ubbadub remembers S’hampton at all.⁵ | Yrs affec F. D.

I shall certainly come on Friday⁶