In A, what follows the comma is essentially a noun phrase decribing “Essay on Heat and Light”. So the “essay” is a critique and a vision.

a critique of all chemistry since RB is parallel to a vision of a new chemistry that Davy hoped to found

D is a participal phrase. The problem here are the nouns that follow the participal ‘critiquing’: (1)all chemistry from RB and (2)vision of new chemistry that D hoped to found.
This doesn’t make sense because here it seems that Davy presented the results ciritiquing past work and his own vision.

Also, critiquing all chemistry from RB forward… “forward” is akward here. Its probably better to use “onwards” or re-cast the sentence as in choice A.

-BM-

@ BM - Tx much for clarifying. Have a quick question, in your explanation "In A, what follows the comma is essentially a noun phrase decribing “Essay on Heat and Light”. So the “essay” is a critique and a vision." can you help me understand how you determined that the phrase following 'essay' is describing essay rather than explaining the impact of the total action of Davvy (Davvy presented an essay)?

Pls clarify.

crackgmat007 wrote:@ BM - Tx much for clarifying. Have a quick question, in your explanation "In A, what follows the comma is essentially a noun phrase decribing “Essay on Heat and Light”. So the “essay” is a critique and a vision." can you help me understand how you determined that the phrase following 'essay' is describing essay rather than explaining the impact of the total action of Davvy (Davvy presented an essay)?

Pls clarify.

I see what you mean.

I think this sentence could end both ways, i.e. with nouns describing "essays" OR a description of the impact of HD's presentation. If it is the earlier, then what follows the comma is a noun phrase (a critque and a vision, as in A).

If the impact of the presentation that needs to be conveyed, then a participal phrase should follow (as in D and E). But there are problems of parallelism/meaning with these two choices:

D. critiquing (all chemistry from RD forward) and also (a vision of ..)
-here the stuff in brackets are parallel to each other but this conveys a nonsensical meaning I mentioned in the previous reply.

E. critiquing (all chemistry from RD forward) as well as (his own envisioning of)
- again here, (among other problems) you see the same meaning problem in D.

Did I answer your question?

-BM-

thanks much for the clarification. This helps.