"Yes; because enough air, or oxygen must go through the mesh to support combustion of the flame itself. If it does not get enough it is smothered."
"But where can we get enough gauze to make a cylinder big enough to go around a lamp?"
John laughed at the serious predicament, which expressed itself in the faces of the boys. "That is true," he said; "but if we can get a small piece of tin, we can punch it full of fine holes, and probably make that answer."
"We haven't anything in the way of tin large enough to go around a lamp, but here is a round piece, about three inches in diameter."
"That will answer; punch that as full of holes as possible, and be sure they are very small."
John was already looking around, and soon spied a tree in the distance that looked like a small pine, and beneath that he found some cones, a dozen of which were picked up.
[Illustration: _Fig 14. How John made the Lamp._ _A. Perforated Disk_ _B. Frame of Sticks_ _C. Cloth Covering_ _D. Base Plate._]
"Yes; these cones will burn for some time."
"But they will not make much of a light."
"No; but we are not after a light, but they will do for testing purposes."
The accompanying sketches show how it was made. A plate was used for a base, on which the burning cone was placed. A half dozen twigs were then provided, and these were bent U-shaped, after being secured together at their middle portions, and the lower ends held by a cord, and this was then inverted, and a piece of thin cotton goods, of a single thickness, only was wound around the little frame, leaving an opening at the top, which was covered by the perforated tin disk.
"There, now we have an article which provides for the admission of air, through the cotton goods, and the product of combustion can escape through the perforated opening at the top."
The boys danced around with joy, when the cone was ignited, and a bale, which was simply a string, attached, so it could be carried conveniently.
This time they went on, far beyond the place where the poor dogs lay. Occasionally John would lower the device, and when it descended too far, the knot would begin to smoke, and this was explained by the statement that as it went into the carbon gas, less and less air was supplied, which caused the flame to die down.