When steam navigatiou began, the wildest speculations were indulged in as to speed ; but all of thein were doomed to be falsified by the resultB. With the hosts of improvements yearly adopted. the original speed of eight miles per hour has scarcely been doublod. On the average it has not ; the latest ocean-going 8teamers only aecoinplish fifteen miles, In smooth rivers and in narro w channels much higher rates of speed have bean obtainod ; but the average of all kinds of steamers, river and ocean, is from twelve to sixteen miles per hour, and the problem that still vexes engineers is how to obtain a much higher rate of speed. When that will be solved no one can teil ; the ocean is a mighty monster and will not readily be subdued.