From Horace Darwin to G. H. Darwin [2 September 1867]

Monday

Dear George

Will you send me your Trigonometry by post as soon as you can if you don’t want it. I have lost mine. I want you to teach me when you come   I have got to sin(A+B) = sinA cosB + cosA sinB & what’s more I know it. F. has just come back from Wales & seems to have had joly fun.

I remain your affec bro | H Darwin

Please cite as “FL-1380,” in Ɛpsilon: The Darwin Family Letters Collection accessed on 27 April 2024, https://epsilon.ac.uk/view/darwin-family-letters/letters/FL-1380