By devising an instrument made from a rod, wire, and lead balls, and

By devising an instrument made from a rod, wire, and lead balls, and employing uncommonly precise measurements, in 1797–1798 Henry Cavendish’s apparatus enabled him to arrive at an astonishingly accurate figure for the weight of the earth.

Issues: Parallelism | Modifier | Construction

Analysis:
1. The sentence talks about how Henry Cavendish was able to at a figure. Hence, the actions "devising" and "employing" should point to correct noun i.e. Henry Cavendish and not "Henry Cavendish's apparatus" because "apparatus" can not perform those actions. Also, "Henry Cavendish" should immidiately follow the modifier "By devising...,"
2. In the clause "By devising..." there are two sub-clauses for the two actions i.e. "By devising.. and employing...". The correct chioce should have those actions in parallel.


A. By devising an instrument made from a rod, wire, and lead balls, and employing uncommonly precise measurements, in 1797–1798 Henry Cavendish’s apparatus enabled him
- "Henry Cavendish’s apparatus" creates meaning issue with modifier that precedes it
- "him" does not have an antecedent.

B. In 1797–1798, by devising an instrument made from a rod, wire, and lead balls, and employing uncommonly precise measurements, Henry Cavendish’s apparatus enabled him\
- "In 1797–1798" is mis-placed
- "Henry Cavendish’s apparatus" creates meaning issue with modifier that precedes it

C. Henry Cavendish devised an instrument made from a rod, wire, and lead balls, and employed uncommonly precise measurements, and in 1797–1798 was able
- Meaning issue with the option. (Looses the causality between the two parts of the sentence)

D. Having devised an instrument from a rod, wire, and lead balls, and employment of uncommonly precise measurements, Henry Cavendish in 1797–1798 was able
- "Having devised... and employment..." has parallelism issue

E. By devising an instrument made from a rod, wire, and lead balls, and employing uncommonly precise measurements, Henry Cavendish was able in 1797–1798

Answer: E.

The sentence tells us that in 1797 – 1798, Henry Cavendish was able to arrive at an accurate value of the weight of Earth. He was able to do this by doing two things – by devising an instrument made from a rod, wire and lead balls and by employing precise measurements. These two things should be in parallel.

(A) By devising an instrument made from a rod, wire, and lead balls, and employing uncommonly precise measurements, in 1797–1798 Henry Cavendish’s apparatus enabled him
(B) In 1797–1798, by devising an instrument made from a rod, wire, and lead balls, and employing uncommonly precise measurements, Henry Cavendish’s apparatus enabled him

Look at the structure of the sentence in option (A) – it starts with an adverbial prepositional modifier. This should be followed by the subject who did the devising and the verb which tells us what was accomplished ‘by devising…’
The modifier ‘By devising … measurements’ should be followed by Henry Cavendish because he was the one who devised the instrument.
Next, we should have the verb ‘was able.’ The prepositional modifier tells us ‘how’ he was able to arrive at the accurate figure - by devising an instrument...

If we follow the prepositional modifier by ‘Henry Cavendish’s apparatus enabled him,’ we are implying that the apparatus devised the instrument. But we know that only Henry Cavendish could have devised the instrument.
Hence both options (A) and (B) are eliminated.

(C) Henry Cavendish devised an instrument made from a rod, wire, and lead balls, and employed uncommonly precise measurements, and in 1797–1798 was able

Option (C) de-links the devising of the instrument and arriving at the figure for weight. The sentence tells us that he was able to arrive at an accurate value by using this instrument that he devised and employing precise measurements but option (C) puts the three verbs in three verb phrases making them three separate actions.
Henry devised… and employed … and was able to …
Hence, option (C) does not give accurate meaning.


(D) Having devised an instrument from a rod, wire, and lead balls, and employment of uncommonly precise measurements, Henry Cavendish in 1797–1798 was able

The devising of the instrument should be parallel to employing of precise measurements as we discussed at the beginning. Option (D) errs on this. It uses ‘having devised (perfect participle)… and employment (noun) of …’
The two are not parallel. Hence option (D) is eliminated too.

(E) By devising an instrument made from a rod, wire, and lead balls, and employing uncommonly precise measurements, Henry Cavendish was able in 1797–1798

Option (E) uses the parallel structure ‘By devising … and employing…’ for the modifier and follows it with the required subject and verb ‘Henry Cavendish was able .. ‘

Answer (E)

Dear manhasnoname,

I'm happy to respond.

My friend, the entire issue of "essential" vs. "non-essential" modifiers applies only to noun modifiers. The Touch Rule also applies only to noun modifiers.

Verb modifiers are a completely different world. It doesn't make sense to talk about an "essential" or "non-essential" verb modifier, and placement of verb modifiers is considerably freer than that of noun modifiers.

The preposition "in 1797-1798" is a verb modifier. It is an adverbial phrase, playing the role of an adverb. It is fine in (E), not set off by commas. As a verb modifier, it is neither "essential" nor "non-essential." There is absolutely no problem with its placement or use in (E), the OA.

Does all this make sense?
Mike

Dear Bounce1987,

I'm happy to respond.

For starters, I will recommend this blog article:
Rhetorical Construction on the GMAT Sentence Correction

A sentence is rhetorically effective if it is clear, direct, powerful, and persuasive. If a sentence is too wordy, that's a rhetorical issue. If the sentence is neither direct nor forceful, that's a rhetorical problem. For example, does the sentence make the focus the subject and does it locate the main activity in the main verb? Having the action as a verb vs. a noun is often a rhetorical issue. Is the focus-noun the subject or hidden in a prepositional phrase? Also, verbs in the passive voice are 100% grammatically correct but often present rhetorical issues. Another issue, in a list, is: what governs the order of the list? Is it logical? chronological? or just random? Random organization is not rhetorically sound. Finally, there's that very hard-to-articulate realm of rhetoric—whether something would sound "natural" or "awkward" to a native speaker. This is particularly tricky: on the harder SC, the GMAT loves to create incorrect answer choices that are 100% grammatically correct but some combination that no native speaker ever would say.

The best way to improve one's understanding of rhetoric is to make a habit of doing challenging reading every day.

Does all this make sense?
Mike

Dear oishik2910,

I'm happy to respond.

First of all, if you want the attention of another member on GC, it's best to use the "mention this user" feature.

Also, you would make your questions much clearer and less of a challenge to interpret if you used quote marks (and preferably color) to set off your words from what you are quoting. For example,
You wrote: "sir I am generally confused with usage of having and consider the same as wrong but in option D if both parallelism had a structure of: having devised and having employed would it have been correct"
I suggest: "sir I am generally confused with usage of "having" and consider the same as wrong but in option D if both parallelism had a structure of: "having devised" and "having employed" would it have been correct."
The quote marks are necessary for clarity. The color adds additional clarity.

Here is the version you suggest:
Having devised an instrument from a rod, wire, and lead balls, and having employed uncommonly precise measurements, Henry Cavendish in 1797–1798 was able . . .
This is 100% grammatically correct, but it is still awful. Rhetorically, this sounds too stilted and hyper-formal--it doesn't sound natural at all. No native speaker would say this.

Remember that the GMAT SC is not simply a test of grammar. On the GMAT SC, grammar & logic & rhetoric all work together to bring forth meaning.

Does all this make sense?
Mike

This problem is simplified dramatically if we are able to logically see what the modifier is modifying - Henry or Henry's apparatus? It is of course the former.

Modifier Error
Who performed the action of "devising an instrument"? Henry of course.

Eliminate A and B - states that Henry's apparatus performed the action

Change in meaning Error - C
The intended meaning of the sentence is that HC's apparatus enabled him to arrive at an astonishingly accurate figure, but (C) changes this meaning such that the cause-effect relationship between what enabled Henry to obtain these accurate measurements is eliminated.

Eliminate C

Parallelism Error - D
"having devised...employment of" are not parallel

E corrects the modifier error in the original sentence while maintaining parallel grammar. Correct

The use of two "and"s is not really incorrect and could be taken as a way for the author to indicate that the first two events occurred close to each other in time and the third followed later. In this case, the use of two "and"s doesn't result in a sentence that clearly expresses the point to be made. All the same, that move could be used effectively in some contexts.


Here's the relevant portion of choice (A).

in 1797–1798 Henry Cavendish’s apparatus enabled him

In the past, in GMAT Sentence Correction, a subject pronoun may have been considered lacking an antecedent if the only possible referent were the possessive form of a noun. However, more recent questions seem to indicate that the convention has been changed, as the correct answers to these questions have contained subject pronouns that seem to refer to referents derived from possessive forms of nouns.

So, under what seems to be the current convention, there is no pronoun issue in choice (A).

Dear Mike, I selected E using POE but my question is.....is it okay to have a split in able + to?

For e.g.:
Ver#1: After trying for several years, Sam was able to pass the GMAT in 2016

Ver#2: After trying for several years, Sam was able in 2016 to pass the GMAT.

Is is valid? "Sam was able in 2016 to pass the GMAT" ?

Should " in 1797–1798" be set off by commas to make it non-essential modifier? Otherwise, it sounds awkward. Doesn't it? Could someone please clarify? Thanks!

Dear kawaljeet,

I'm happy to respond.

The short answer is: yes, that's perfectly fine. The prepositional phrase "in 1797-1798" is a verb modifier, an adverbial modifier. Unlike noun modifiers, adverbial modifiers are much freer in the rules about their placement. It's perfectly fine to put this modifier between "able" and "to arrive." In fact, this is a sophisticated structure that is slightly rarer, and these facts can make it particularly challenging for non-native speakers to accept.

Does all this make sense?
Mike

Skywalker18
Just to add some background to what MartyTargetTestPrep wrote about possessive antecedents.

It's not clear whether GMAC ever adhered to the rule.

It is now evident that on the GMAT, as long as meaning is clear, both object and subject pronouns may have a possessive noun as an antecedent.

After much research, I wrote a post that discusses the "possessive poison" guideline in which I cite four of at least six official questions whose correct answers violate the possessive poison guideline. That post is HERE

E is corerct
Parallel - devising ,........employing
SV - Henry ....was

Hi Ilhomjon98,

What we see in option E is one way to say that someone was able to do something for (normally) the first time. Think of this as an achievement. Maybe there were no estimates before this, or there were no estimates this accurate. For example, in "after taking the GMAT a few times, he was finally able, in 2020, to get a good score", we're not really saying that he couldn't get a good score after 2020. That is, that sentence doesn't tell us anything about what happened after 2020, but it does point out that something happened in 2020. That's what this sentence does: it tells us that something was achieved "in 1797–1798".

By devising an instrument made from a rod, wire, and lead balls, and employing uncommonly precise measurements, in 1797–1798 Henry Cavendish’s apparatus enabled him to arrive at an astonishingly accurate figure for the weight of the earth.

(A) By devising an instrument made from a rod, wire, and lead balls, and employing uncommonly precise measurements, in 1797–1798 Henry Cavendish’s apparatus enabled him
By devising an instrument..and employing…, incorrectly modifies Cavendish’s apparatus. Eliminate

(B) In 1797–1798, by devising an instrument made from a rod, wire, and lead balls, and employing uncommonly precise measurements, Henry Cavendish’s apparatus enabled him
Same as A. Eliminate B

(C) Henry Cavendish devised an instrument made from a rod, wire, and lead balls, and employed uncommonly precise measurements, and in 1797–1798 was able

Cavendish
Devised an instrument
Employed uncommonly precise measurements
Was able to arrive
Option C presents three independent actions. This alters the intended meaning of the sentence. Eliminate.

(D) Having devised an instrument from a rod, wire, and lead balls, and employment of uncommonly precise measurements, Henry Cavendish in 1797–1798 was able
Option D breaks parallelism. Eliminate

(E) By devising an instrument made from a rod, wire, and lead balls, and employing uncommonly precise measurements, Henry Cavendish was able in 1797–1798
By devising… and employing…, Henry Cavendish was able in 1797–1798
Correct.


VP
GMAT Verbal SME

Here the subject is Henry Cavendish's apparatus, rather than Henry Cavendish himself. The inferred meaning is that Henry Cavendish's apparatus devised an instrument, which makes no sense. Reject (A)


Same error as is in (A). Henry Cavendish's apparatus did not devise anything. Henry Cavendish did. Reject (B)

The inferred meaning of (C) is that Henry Cavendish devised an instrument, employed uncommonly precise measurements and calculated the weight of the earth - all of them independently. This is not the intended meaning, as the first two actually helped him in calculating the weight.
Also, devised an instrument, employed uncommonly precise measurements and was able to are not in parallel.
Reject (C)


Same discrepancy in the inferred meaning, as in (C). Also, Having devised an instrument and employment of uncommonly precise measurements are not in parallel. Reject (D)



Contrary to (C) and (D), (E) clarifies that by doing X and Y, Henry Cavendish was able to do Z.
Also, devising an instrument and employing uncommonly precise measurements are in parallel and are joined with an and. Since third clause is the impact of first and second, and is required between first and second.

Approve (E)

Please let me know if I am going wrong anywhere. I am writing my GMAT on 23rd June 2021

Many people consider it acceptable to add place a comma before an "and" that connects an additional predicate to a sentence because commas can be added to sentences with some discretion.

Consider this example:

John sailed over the horizon one fine morning, and never came back.

In that example, the comma before "and" is not necessary, but it serves the purpose of creating a pause and, thus, emplasizing the second predicate "and never came back."

So, even though "and never came back" is not an independent clause, many people would consider that sentence correct.

Thus, such a comma placement does not render a sentence incorrect, at least not in the eyes of many people, and therefore, eliminating an SC choice because of the presence of such a comma is not the way to go.

In fact, in GMAT SC, the presence or lack of a comma is only very rarely a reason to or part of a reason to eliminate a choice.

So, the safest way to eliminate choice (C) of this question is to notice the flaw in the meaning conveyed by that version.

Mary's explanation is solid.

I would also add that C is, arguably, not grammatically correct.

b]Henry Cavendish devised an instrument made from a rod, wire, and lead balls, and employed uncommonly precise measurements, and in 1797–1798 was able...[/b]

We have some parallelism happening here (and a moment of parallelism within parallelism, when listing what the instrument was made out of). But at the highest level we're listing what Cavanedish did:

Henry Cavendish DEVISED [a thing], and EMPLOYED [some things], and WAS ABLE TO [do a thing].

So the structure is: Henry Cavendish VERBED, and VERBED, and VERBED...

Items in parallel structure typically need only ONE conjunction (the exception would be something like "X AND Y AS WELL AS Z."

But you should not include multiple 'ands' for the same list in parallel structure.