"Light travels one hundred and eighty-six thousand miles a second," stated Mark, who remembered his physics. "That's more than seven times around the earth in a second." "Correct," said Mr. Roumann with a smile. "But sound, as you know, only goes a little over a thousand feet a second, at a temperature of thirty-two degrees above zero. In a warmer atmosphere it travels slightly faster. We are going much faster than sound ever travels. A cannon ball will travel about three thousand feet per second, so we are even going to beat cannon balls. At least, we hope we are, when we get beyond the earth's atmosphere." "That's going to be terrific speed," remarked Jack dubiously, as if there was some risk in it. "You need not worry," said Mr. Roumann. "You know we are building the Annihilator with a double shell, with a space between the two walls." "Yes?" said Jack questioningly. "Well, in that space I intend to put a new kind of gas, that will absorb all the heat that may be generated by our flight through space," went on Mr. Roumann. "Now that you know you have nothing to fear, let us go on with the work." CHAPTER VIII A MYSTERIOUS THEFT "Would yo' kindly permit me t' prognostigate yo' attention fo' de monumental contraction of impossibilitiness in de circomlocution ob attaining de maximum nutrition ob internal combustion?" asked Washington White about an hour later, as he poked his head into the workshop, where the professor, the boys and Mr. Roumann, together with the machinists, were busily engaged. "What's that, Wash?" asked Jack with a wink at Mark. "Would you mind saying that over again?" "Not in de leastest, Massa Jack," replied the colored man. "What I done intended to convey to de auditory sensibilities ob de auricular nerves ob do exterior contraption ob de--" "Hold on, Washington!" cried Professor Henderson with a laugh. "That sounds as if it was going in be worse than the other. Did I understand you to say that you wanted us to come to dinner?" "Dat's jest it, pertesser. I done 'spress mahself in de most disproportionate language what I knows how, an' yet it seems laik some pussons cain't understand de appreciableness ob simplisosity." "Simplisosity is a new one," murmured Mark, while Washington, with an injured look at Jack, who was laughing, went back to his kitchen to prepare to serve the meal. "I wonder what we'll get to eat when we get up above?" asked Jack, taking advantage of a lull during the meal, when Washington was in the kitchen, for it had been agreed that nothing was yet to be said to the colored man as to their destination, though Andy Sudds knew of their plans. But Andy could be depended on not to talk too much. "Eat?" repeated the professor. "Why, I fancy that we will take enough along from the earth to last us, eh, Mr. Roumann?"