You get in your car to drive to the store (1). you turn the key and the engine starts making a clicking sound, but does not start (2). you think to yourself, "the battery must be dead" (3a), so you go into your neighbor's garage and borrow the battery from your neighbor's car (with permission, of course) and exchange it for the battery in your car (3b). you also put your presumably dead battery in your neighbor's car (4). you figure that if the battery in your car is dead and you replace it with a working battery, then the car will start and your neighbor's car won't start (5). you get in the car again, turn the key, and your car starts right up (6). your neighbor's car does not start (7). you replicate this experiment with 10 sets of cars and batteries and get the same result each time (8). which part is an experiment?

“dear sir: it is with great reluctance, i trouble you on a subject, which does not fall within your province; but it is a subject that occasions me more distress, than i have felt, since the commencement of the war; and which loudly demands the most zealous exertions of every person of weight and authority, who is interested in the success of our affairs. i mean the present dreadful situation of the army for want of provisions, and the miserable prospects before us, with respect to futurity. it is more alarming than you will probably conceive, for, to form a just idea, it were necessary to be on the spot. for some days past, there has been little less, than a famine in camp. a part of the army has been a week, without any kind of flesh, and the rest for three or four days. naked and starving as they are, we cannot enough admire the incomparable patience and fidelity of the soldiery, that they have not been ere this excited by their sufferings, to a general mutiny or dispersion. strong symptoms, however, discontent have appeared in particular instances; and nothing but the most acitive efforts every where can long avert so shocking a catastrophe.” what’s the central idea?