as throwing

[Ahmed Samir Darwish]

In LIFE AND LETTERS OF CHARLES DARWIN Volume 2, Darwin was talking about a paper on Drosera:

I began this work on Drosera in relation to GRADATION as throwing light on Dionaea."

The subject of "throw" is "gradation" or "Drosera"?

 

[The Newt]

The idea seems to be "because it (the work) would throw light on Dionaea."