We understand that a low pressure steam-)oat named the ' Jacob Strader,' has been re-ently built for the Cincinnati and Louisville Mail Co., to run on the Ohio river. All the steamboats running on the Western Waters are driven by high pressure engines, but this boat is not the first low pressure that has been tried on the Ohio or Mississippi. Excellent low pressure steamboats have been faithfully tried on the Mississippi, but failed to work well in such muddy waters excepting for a short time, and hence they were abandoned. At the present moment there are 1,205 steamboats in the United States, and Out ot that number there are only 362 with low pressure enginesall the rest being high pressure; the latter are nearly all employed on the Western rivers ; Pittsburg has 101 high pressure boats ; Cincinnati 104, St. Louis 126, New Orleans 111 and Buffalo in New York has 34the rest being owned in various other cities South and West, and a number on the north-western lakes. The great number of steamboat accidents in our country caused by the explosion of steam boilers, is to be attributed to the great number of high pressure engines employed. It has long been a desideratum to obviate the dangers of explosions, and there can be no doubt that if the proportion of our high pressure to those of our low pressure steamboats were reversed, the number of boiler explosions would decrease exactly in the same ratio. On the Ohio river, where there are so many high pressure boats, the extra weight of the machinery for low pressure boats has always been a great obstacle in the way ot low pressure boats on that river, owing to the very low state ot the water during the dry period of the year. As no effort hitherto made to introduce low pressure boats on the Western waters, has proved successfu every one being a practical failurewe cannot place much confidence in any new effort not, at least, until it has had a fair trial for some time. Some have supposed that the in teni boats contained considerable of the chlo rate ot potash,and that when the boiler flues by neglect or otherwise became red-hot, this substance exploded and tore the boiler to frag ments. Others believe that all the explosions on the Western boats are attributable to over pressure of steam, and look upon the incrus tation theory as a chimerical one. Were it possible, however, to prevent scale in the boilers of our Western steamboats, by the use of pure feed water, and at the same time use condensers, grand and useful results would be obtained. Is it not possible that a good surface condenser may yet accomplisl these two objects ' What has become of the information which should have been spreai befor the people more than a year ago on the subject ot steam engines, condensers, boilers c, by a Committee appointed by the Secretary ot the Navy, which took nearly two years to collect information. It appears to u, that alter so much labor and money spent, the people should know whether the members o the Committee performed their duties in a proper and masterly manner, or whether they neglected to do so. We hope that low-pressure condensing steamboats will yet be rendered practicable on our Western waters, for they are by far the most comfortable in every sense for passengers, and besides, they are more safe, with respect to lite, and more economical with regard to fuel.