i868 i88i] JODRELL LABORATORY 417 



used until well provided ; and the mere fact of the instruments Letter 745 

 being ready may suggest to some one to use them. You at 

 Kew, as guardians and promoters of botanical science, will 

 then have done all in your power, and if your Lab. is not 

 used the disgrace will lie at the feet of the public. But until 

 bitter experience proves the contrary I will never believe that 

 we are so backward. I should think the German laboratories 

 would be very good guides as to what to get ; but Timiriazeff 

 of Moscow, who travelled over Europe to see all Bot. Labs., 

 and who seemed so good a fellow, would, I should think, give 

 the best list of the most indispensable instruments. Lately I 

 thought of getting Frank or Horace to go to Cambridge for 

 the use of the heliostat there ; but our observations turned 

 out of less importance than I thought ; yet if there had been 

 one at Kew we should probably have used it, and might have 

 found out something curious. It is impossible for me to 

 predict whether or not we should ever want this or that 

 instrument, for we are guided in our work by what turns up. 

 Thus I am now observing something about geotropism, and 

 I had no idea a few weeks ago that this would have been 

 necessary. In a short time we might earnestly wish for a 

 centrifugal apparatus or a heliostat. In all such cases it 

 would make a great difference if a man knew that he could 

 use a particular instrument without great loss of time. I 

 have now given my opinion, which is very decided, whether 

 right or wrong, and Frank quite agrees with me. You can, 

 of course, show this letter to Hooker. 



To F. Ludwig. Letter 746 



Down, May 29th, 1878. 



I thank you sincerely for the trouble which you have 

 taken in sending me so long and interesting a letter, together 

 with the specimens. Gradations are always very valuable, 

 and you have been remarkably successful in discovering the 

 stages by which the Plantago 1 has become gyno-dicecious. 

 Your view of its origin, from being proterogynous, seems to 

 me very probable, especially as the females are generally the 

 later-flowering plants. If you can prove the reverse case with 



1 See F. Ludwig, Zeitsch. /. d. Geo. Naturwiss., Bd. LI I., 1879. Pro- 

 fessor Ludwig's observations are quoted in the preface to Forms of 

 Flowers, Ed. II., p. ix. 



VOL, II. 27 



