"First, there were the Detorium-driven rockets. Fine ships that opened up the realm of travel in outer space." His voice was firm, stringent with his inner excitement, his faith in his idea. "In fact, it was just such a ship as this that Joc Kenton, Mars to you folks, was on when they made their first landing on Mars. These ships had their good points and still are excellent over short distances but certainly are of no use for intergalactic flight. They are much too slow, requiring more than a lifetime to make the trip there and back. "Then came the interstellar drive, the method we are now using. This drive, utilizing Carbolium which we have to manufacture, makes full use of space as a medium of travel. There's only one catch. We can make only a certain amount of Carbolium, and the costs of making it are astronomical. However, no matter what the expense, the supply is limited. Still, everything's fine. We use the old rockets for short distances and the interstellar drive for intergalactic trips." He paused a minute to let it sink in. "That is everything _was_ fine. As you know, we have found another planet, remarkably similar to Earth in the Eastrex Galaxy, and have succeeded in setting up a colony there. This presents problems. For one, since we can send only four ships a year to Naver, this new planet, our colonizing is going to be slowed down to a crawl. Also, we will have a mighty hard time trying to get supplies and everything else that a new colony needs to Naver within a reasonable length of time. In other words, what we need is a ship that will be cheap to run, fast enough to get there and get back again and also safe enough to carry passengers and cargo, even in small amounts. You've heard of this problem before; I know you've tried independently to work it out and have not had much luck. I think we might have an answer now. "How many of you have shot a rifle or are familiar with a gun?" The expectant faces had gone blank. What was he leading up to anyhow? Still, a large number of hands cautiously worked their way into the air. "All right. All you have to do right now is forget about space ships and concentrate on a rifle and a bullet." There was beginning to be the muttering and stirring of a confused group of people. Bronsen's muscular hands gripped the table eagerly. They were confused, but they were also interested. "You are familiar with the fields and grooves of a gun barrel," he continued, "and you know they are there to give the bullet a spin when it is fired. Now what happens to a bullet when it is fired from a smooth barrel, with no grooves? It is inaccurate, wobbles, has less power and eventually turns end over end. Now, take the grooved rifle barrel. The bullet is given a spin, it has many times the velocity of the other, it has a straight line accuracy due to the spiral motion--keep these last two points in mind--and providing the rifle is aimed right in the first place, will hit the target."