Some exceedingly funny and strange statements are now being published about hot air engines and their authors. Pliny Miles delivered a lecture in this city on the 1st inst., on Iceland, and after stating that this continent was first discovered by the Norsemen, under Eric the Red, he said, Capt. Ericsson is believed to be one of his lineal descendants. It no doubt took more labor to make this discovery than to invent the hot air engine. Some of our daily papers have endorsed this discovery of the descendant of Eric the Red. The only powerful rival to the hot air engine, is Andrew Jackson Davis, the Seer. He, by the power of his will, has hut to look into his press room, nod his head, and off goes his printing press. The American Gazette, Phila., says, It is stated by those who have seen the caloric engine in operation, that if no attention is paid to it, the only result will be, that when the fire goes out, the machinery will stop. These innocent remarks are made to show what a wonderful virtue there is in the caloric engine. We are led to infer from them that when the fires of a steam engine go out every person must run for life or death, for fear ot an explosion, or that the machine will work away without any fuel at all. Since the Ericsson has arrived at Alexandria, it has been visited by the great folks at Washington, and Capts. Ericsson, Sands, and Lowber, have made reports to Hon. J. P. Kennedy, now ex-Secretary of the Nivy.— Capt. Ericssons letter says, the motion of the paddle wheels was more continuous than that of steamships, owing to the powerful momentum of the double pistons which form a main feature in the caloric engine. This is really a captivating feature in engineering. The next time Messrs. Stillman,Allen & Co., or Charles W. Copeland design a pair of marine engines, they must put in four single acting cylinders, instead of two double ones, because you see gentlemen, to give them a I more powerful momentum, all you have to do is to increase the number of the pistons. By the reports of Capts. Sands and Lowber the Ericssons wheels made only 6J revolutions per minufcejn her trip to the Potomac ; taking the (ILujjBbr of her wheels and allowing 25 per ceSHr slip—a fair allowance— she made only 5J miles per hour—this will never do. A correspondent of the Brooklyn Eagle—an engineer—says, she would take 48 days to go to Liverpool at the rate she took to go from New York to Alexandria.— He advises the owners to own up at once. A proposition was made to that generous old gentleman, Uncle Sam, to build him two war ships with Ericssons engines. The Hon. J. P. Kennedy calls hot air a new motive powei ; he must certainly be posted up in inventions. It is singular how philanthropic all the owners of doubtful inventions are in respect to the welfare ot Uncle Samuel, for how the hot air engines with most of the machinery above water line, and with single acting cylinders having huge pistons which neither can work, horizontally nor on an incline, can answer for.we.r vessels, we arc at a loss to determine. A remarkable instance ot collateral testimony to prove what we have said about Stirlings claims to the hot air engine has just been presented. A number of the 11 Glasgow Advertiser of January says, that about thirty years ago a boat named the Highland Lad, fitted with hot air engines invented by Dr. Stirling—the engines were built by Claud Girdwood—ran for some time on the Clyde, but the heat soon destroyed the furnaces and cylinders ; it says that Ericssons engines are but a modification of Stirlings. A nephevv ot Dr. Stirlings, living in Canada, in a letter to the Montreal Transcript, 31st January, which we have before ns, says, he saw the hot air engine of his uncle in Claud Gird-woods Foundry. Thus two witnesses, unknown to one another, and living three thousand miles separate, have given testimony in favor of all we have stated. But to put this question at rest for ever, and to nail the. insinuations thrown out by some ot our daily papers in the teeth of their authors, respecting the truth ot what we have said, we say that a description with two engravings ot Stirlings hot air engine Was published in our country in 1S28, on pages 314,15, and 16, of the Jour, of the Franklin Inst., Vol. 5, where our readers will find said illustrations and description. We perceive that since we referred our readers to documents where they would find a description of Stirlings hot air engine, in the London Mechanics Magazine, that the said information has been published by a cotem-porary. We are glad to see that it is published, and that our cotemporary and others are now viewing the matter in its true light, yet let us say that a very minute and lull description of Stirlings hot air engine was published by us five years ago on pages 134 and 142, Vol. 3, Scientific American, before one was commenced in this country by Capt. Ericsson, and which embraces his principle of refrigeration, and as it respects economy of size far surpasses it. It those professedly eminent and literary men who have called this caloric engine a new power, had been constant readers ot the Scientific American, they would not have made themselves so eminently ridiculous as they have done by exposing their ignorance about inventions. On the 3rd inst., Mr. G win, from the Naval Committee in the Senate, moved that a frigate be constructed with Ericsson engines, at a cost not exceeding $500,000. The motion was rejected by a vote of 27 nays, 19 yeas. The owners of the Ericsson, if the improvement is so superior to steam as is alleged, need not regret the decision, for they will be able to compete and surpass all our steamships. It is said that the Ericsson is going to Australia, and from thence to England. It would please us better if it made its first voyage from New York to Liverpool. Give the Ericsson a fair trial, and let her by deeds prove that all those who have expressed themselves on the negative side of the question, have been mistaken. We make this assertion, that in three years, perhaps less, a hot air engine in a ship will be among the things that were.