1. Members may be in the same line of thought; that is, they may denote related events succeeding each other in time, or they may tell similar things about the same subject, or the second may be added to the first by way of supplementing or explaining it, etc. Sentences of this kind are very common; as, “We consecrate our work to the spirit of national independence, and we wish that the light of peace may rest upon it forever.”—Webster.
Connective.—For members in the same line of thought the typical conjunction is and. All the other connectives so used are equivalent to and, though they may have a slight additional meaning. These are,—
(a) The coördinating conjunction nor or neither, equivalent to and not; as, “Bolts and bars are not the best of our institutions, nor is shrewdness in trade a mark of wisdom.”—Emerson.
(b) While.—This must be carefully distinguished from the subordinating conjunction while, and from while used to coördinate but equivalent to but; as, “His lower limbs were sheathed like his body in flexible mail, securing the legs and thighs, while (= and) his feet rested in plated shoes which corresponded with the gauntlets.”—Scott.
A common type of sentence which it seems best to classify here is one in which the first member is imperative, the second declarative, and the two joined by and; as, “Tell me what you like, and I will tell you what you are.”—Ruskin. This is equivalent in meaning to a complex sentence containing a clause of condition,—“If you tell me what you like, I will tell you what you are.” But, inasmuch as the author used and between his two propositions, it would seem that he intended the condition to be equally important with the second statement. Sentences of this kind have a directness of appeal to the reader that gives them a peculiar force.
2. The members of a compound sentence may denote contrasting thoughts; as, “In cities we study those around us, but in the retirement of the country we learn to know ourselves.”—Longfellow.
The second member often denotes a thought not to be expected after the first has been accepted; as, “Boys are capital fellows in their own way, among their mates; but they are unwholesome companions for grown people.”—Lamb. This sentence reminds us of the complex sentence containing a clause of concession, for it might easily be recasted into one,—Though boys are capital fellows, etc.
Connective.—The typical conjunction for this sentence is but; all the substitutes for but are merely its various equivalents. These are,—
(a) The conjunctions yet, while, and yet, whereas; as, “It is no longer a reality; yet it was one.”—Carlyle.
(b) The adverbs still, only, nevertheless, however. These are conjunctions when used alone between independent propositions, adverbs when associated with but. They all imply an opposition between the two members; for example, “He is glad of his pay—very properly so, and justly grumbles when you keep him ten years without it—still, his main notion of life is to win battles, not to be paid for winning them.”—Ruskin.