But were they to be saved? The Sirians decided they must destroy the works and the people on Venus, so they made one desperate effort. They had at least sixty hours to work in, and now they had a plan that would require time. They retired some hundred miles from the planet, then the entire fleet, torpedo-ships, cargo boats, and the entire body guard of the Sphere lined up, and then switched on powerful attractor beams. Immediately, the combined effect of over three million of these emanations took hold on the planet, and great tides began to rise in its mighty oceans. Many lives were lost in the seaside towns, when the tremendous waves rushed in over the land. But astronomers on the planet and most of the System's scientists were there to watch the Sirians on Mars through their great telescopes. And these astronomers saw what the Sirians intended, and saw that they were well on their way to fulfilling their aim. * * * * * A planet is balanced in its orbit about its parent sun with the delicacy of a diamond on a jeweler's scales. But, like the diamond, if it be displaced by some force, it reaches a new state of equilibrium. Thus, if the diamond is further lowered in the scale by adding a small weight, it soon reaches a new point of equilibrium. No conceivable force, therefore, could be great enough to displace the planet in its orbit more than a few million miles by pulling it either in toward the sun, or out from it, and as soon as that force was released, it would spring back to its original position as the diamond would regain its balance on removing the disturbing weight. For the sun pulls on a planet with a titanic force; it draws it in with the apparent force gravity, and another similar, but opposite force, centrifugal force of its revolution in its orbit, is constantly tending to throw it into the depths of space. These are the two forces that are always balanced. Suppose the planet is drawn nearer the sun; it revolves in a smaller orbit--and it revolves in that smaller orbit with a higher speed--for it has fallen in toward the sun; it has gained speed as any falling body would. It has gained speed in the direction of the sun, but this has operated to increase its rotational speed. Thus it has gained a greater centrifugal force--you can see the effect with a bit of chalk on the end of a string. The smaller the circle it swings in, the greater the tendency to fly outward. But as long as we continue the force that was added to draw it in, it will remain in equilibrium. Remove this extra force and at once the planet will fall away from the sun, losing speed as it does so, till it has reached a point where it is once more in equilibrium with the force drawing it inward.