Darwin's to which this is a reply, nor, indeed, any of his letters to
Forbes. The date of the letter is fixed by Forbes's lecture given at the
Royal Institution on February 27th, 1846 (according to L. Horner's
privately printed "Memoirs," II., page 94.))

Wednesday. 3, Southwark Street, Hyde Park. [1846].

Dear Darwin

To answer your very welcome letter, so far from being a waste of time, is a
gain, for it obliges me to make myself clear and understood on matters
which I have evidently put forward imperfectly and with obscurity. I have
devoted the whole of this week to working and writing out the flora
question, for I now feel strong enough to give my promised evening lecture
on it at the Royal Institution on Friday, and, moreover, wish to get it in
printable form for the Reports of our Survey. Therefore at no time can I
receive or answer objections with more benefit than now. From the hurry
and pressure which unfortunately attend all my movements and doings I
rarely have time to spare, in preparing for publication, to do more than
give brief and unsatisfactory abstracts, which I fear are often extremely
obscure.

Now for your objections--which have sprung out of my own obscurities.

I do not argue in a circle about the Irish case, but treat the botanical
evidence of connection and the geological as distinct. The former only I
urged at Cambridge; the latter I have not yet publicly maintained.

My Cambridge argument (20/2. "On the Distribution of Endemic Plants," by
E. Forbes, "Brit. Assoc. Rep." 1845 (Cambridge), page 67.) was this: That