"So Cap'n Eph thinks he can explain all that, does he?" Mr. Peters said with a queer gurgle in his throat, much as if he were choking. "Wa'al, all I can say is, if he does, it'll be a good deal more'n I've ever heard of his doin' yet. He'll spin a lot of stuff 'bout bendin' the rays, an' after he gets through you won't know quite as much as you did before."
Because he did not understand the meaning of Mr. Peters' remark, Sidney remained silent, and shortly after, the motor having been cleaned thoroughly, he went into the lantern, where he found the keeper awaiting him.
Captain Eph had before him several open books, as if he had been refreshing his memory on the subject of lenses, and immediately Sidney appeared, he said, in an apologetic tone:
"I don't count on bein' able to give you the idee as to the work of the lenses sich as a man ought'er; but I'll try my best, an' if I fail you won't be any worse off than you are now. In the first place this 'ere is what is known as a light of the first order, meanin' the most powerful in the service, an' the lens alone cost about eight thousand dollars. The middle part of the lens is made up of what's known as 'refractors,' which, 'cordin' to my way of tellin' it, are rings of glass makin' a hollow cylinder six feet in diameter, an' thirty inches high. Below it, as is printed here," and Captain Eph pointed with his thumb to one of the open books, "are six triangular rings of glass, ranged in a cylindrical form, an' above it, a crown of thirteen rings of glass, formin' by their union a hollow cage composed of polished glass, ten feet high, an' six feet in diameter, like this 'ere," and Captain Eph waved his hand toward the brilliant apparatus before them, a picture of which is given here.
"But what is the need of making it out of so many pieces?" Sidney asked. "Why wouldn't it be just as well to cover the lamp with a globe, such as is on a house-lamp?"
"That, Sonny, is the hard part of explainin' the business, because I don't know so much about it as I ought'er; but I've heard the inspector talk somethin' like this: The flame of the lamp sends its rays in all directions—up, down, an' sideways; an' what's wanted is to get the light streamin' out in a straight line all around, so the top an' bottom of this 'ere glass cage is put on to bend the rays till they go in the same direction as those in the middle of the flame. 'Cordin' to the inspector, when a ray of light strikes a prism of glass, it turns toward the base, as you'll see in this—wa'al, I don't hardly know what to call it—that I've been drawin' so's you'll understand what the inspector means by bendin' the rays. You'll notice that, except in the middle, the prisms are each set at a different angle, an' with a space between 'em, which allows of catchin' every ray from the lamp—"
"Are you ever comin' down to your supper, or do you count on lettin' all this 'ere food, that's taken me so long to shape up, go to waste jest because you want'er talk 'bout what you don't understand?" was the cry from the kitchen, and Captain Eph said hurriedly as he gathered up the books:
"I reckon we'll have to finish this 'ere talk some other time, for Uncle Zenas does surely seem to be gettin' nervous. He's a mighty handy man 'round a light-house; but I do wish he'd get over bein' so dreadful particular about all hands settin' down to the table the very instant a meal is ready. There are times, like this, when I'd rather linger a little; but I don't dare to on account of his bein' so particular."
Although Captain Eph and Sidney made all possible haste to descend, the cook called out twice more before they could get into the kitchen, and the keeper said soothingly:
"Now, now, Uncle Zenas, you must give a man time to come down-stairs, an' Sonny an' me couldn't have got here any sooner unless we'd tumbled down, which wouldn't have been convenient or comfortable."