“In the first place,” said he, his big eyes looking straight through me with an absorbed expression, as if I were invisible, “I do not use the ordinary fuel for locomotion. Gasoline is expensive and dangerous, and needs constant replenishing. Electricity is unreliable, and its storage very bulky. Both these forces are crude and unsatisfactory. My first thought was to obtain a motive power that could be relied upon at all times, that was inexpensive and always available. I found it in compressed air.”
“Oh!” ejaculated Uncle Naboth.
I am sure he knew less about automobiles than I did, for I owned a small machine at home and had driven it some while on shore. But Mr. Perkins prided himself on being familiar with all modern inventions, and what he did not know from personal experience he was apt to imagine he knew.
“Compressed air,” he observed, oracularly, “is what blows the sails of a ship.”
The inventor turned on him a look of wonder.
“This seems to me like a clever idea,” I hastened to say. “But I can’t see exactly, sir, how you manage to use compressed air for such a purpose.”
“I have a storage tank,” Moit answered, “which is constantly replenished by the pumps as fast as the air is exhausted, which of course only occurs while the machine is in action.”
“But you need something to start the engines,” I suggested. “Do you use gasoline for that purpose?”
“No, sir. I have a glycerine explosive which is so condensed that an atom is all that is required to prime the engines. In a little chamber that contains about a pint I can carry enough explosive to last me for a year. And wherever there is air I have power that is perpetual.”
“That’s great!” cried Uncle Naboth, with an enthusiasm so plainly assumed that Ned and I had much ado to keep from laughing outright.