The New Motive Power

We were present yesterday at the second trial trip of the Caloric ship Ericsson; and are prepared to say without hesitation or reserve, and not merely on our own judgment, but on that of every gentleman in the company, that it proved utterly and beyond the possibility of doubt the existence of a new motive power as sure and efficient as steam, while it is free from all danger of accident, and is vastly cheaper and more manageable. The demonstration is perfect. The age of Steam is closed; the age of Caloric opens. Fulton and Watt belong to the Past; Ericsson is the great mechanical genius of the Present and the Future.

The caloric engine is no hasty product. Twenty-five years ago Ericsson conceived the idea. For twenty-five years he has been engaged in elaborating and perfecting it. In 1833 he propounded it to the scientific world at London. Men of the highest authority, such men as Faraday and Brunel, pronounced it good, and predicted its triumph. But there were practical difficulties. The principle was clear; not so its application. Those difficulties have had to be overcome gradually, one by one. Since the first model engine of five-horse power was constructed, the inventor has built some twelve or thirteen others, in each making some improvement, removing some obstacle. Two years since his invention was complete.

No hindrance remained to be vanquished. He was ready to submit the new motive power to the test of trial on the largest scale. Fortunate beyond other great inventors, at every step he had found means to go forward. And now came the final demonstration. For that means were also found. Enlightened capitalists came forward, and examined, and were convinced. The funds were furnished. It was determined to bring out the machine on a scale unprecedented in the history of inventions.

The Ericsson, a splendid ship of 2,200 tons, was constructed, the machinery built and put on board. The public trial has taken place at the earliest possible moment, if anything, too soon for perfect justice to the invention. Though the engine was unfinished and unable to perform all the work for which it is designed, yet, as many unfavorable rumors had been put in circulation, such as that it could not move the ship from the dock, that the wheels had to be turned by hand, that it was but a vast humbug, with others of the same sort; in order to silence these assertions, and relieve the owners from the sneers and imputations to which they were subjected, as having thrown away their money on a delusion, it was determined to anticipate the time of bringing out the ship, and to submit the caloric engine to public inspection, even in its present imperfect state, and with the certainty that it could not exhibit its whole power.

This was first done in the trial trip of last week, when only the inventor, owners and crew, of the ship were present. Her performance on that occasion we have recorded. Yesterday a second trial was made. This was for the special satisfaction of the members of the press. Representatives were present from all, or nearly all, the journals of the city, including several of the editors-in-chief of the respective papers.

The party was taken from Whitehall at about half past 9 in a small steamer. It was nearly 10 when the Ericsson was put in motion. With the tide and a light breeze against her, she ran down beyond the Narrows, a distance of some ten miles; the tide was also against her in returning; the, run each way was accomplished in about an hour and a quarter, making her average speed about eight miles an hour against the tide.

The time on the passage down was spent in discussing an excellent breakfast, and in examining the engine.

The first thing in the engine which strikes the observer, is the magnitude of the cylinders. These are fourteen feet in diameter, six feet more than those of the Collins’ steamers. There are four in the Ericsson, standing in a fore-and-aft line; two before and two abaft the shaft, and working in pairs upon it. From tile base of the cylinders to the submit is about thirty feet. Each cylinder is double, consisting of what is called a working cylinder and a supply cylinder; the latter being on top and united with the other, though of inferior diameter.

The working cylinder has the furnace under it; in it the active force of the machine is developed in the form of air expanded by heat. The supply cylinder is always cold. The working cylinder is 14 feet in diameter; the piston which plays in it has a superficies of 22,300 square inches. The supply cylinder is 11 feet 7 inches in diameter, and the area of its piston is 14,500 square inches. These pistons are joined by powerful iron rods. The stroke is 6 feet. On the under side of the upper piston are valves, through which the supply of fresh air is drawn after the machine is put in motion.

Over the supply cylinder is a reservoir in which the upward motion of the piston compresses the air, which passes in there through valves. The connexion between the reservoir and working cylinder is by a large pipe running from the former to the base of the latter. The engine is set in motion by pumping cold air into the reservoir, by hand or otherwise.

From the reservoir, through a valve at the bottom of the large connecting pipe, the compressed air is admitted into the working cylinder over the furnace. Here it is instantly heated, and by its expansion drives up the piston, and at the same time compresses the air in tile ply cylinder, and forces it into the reservoir. Then another valve in the connecting pipe opens, and the hot air is let off in to the atmosphere. This removes the pressure that has driven the piston up, when its own weight brings it down again, and the escape valve closes. Then the supply valve opens again, and lets tile cold air in over the furnace; it is heated, and so tile process goes on.

But the great feature of the invention is yet to be described. This is tile apparatus by which the main part of the heat which expands the air in the working cylinder is saved, and made to do duty over and over again. This it is that produces the astonishing economy of fuel, which is one of the great characteristics of the invention.

In a steam engine the heat is used but once; it passes away, and therefore has to be perpetually renewed. In the caloric engine it is economized. This is an immense advantage. The apparatus is formed of iron wire, 1/16 of an inch in diameter, woven into a web dense enough for the holes or meshes to occupy half the surface. Fifty thicknesses, or disks, of this wire cloth are used in each pipe connecting the reservoir and working cylinders. Each disk is 6 feet long and 4 wide, and contains half a million of meshes. They are placed close together in the pipe, between the working cylinder and the two valves which let in the new air and let out that which has been used. Thus all the air which comes in passes through the meshes of the wires, as does all that goes out.

Here lies the wonder of the invention. The heated air in going out leaves its heat in these wires, and tile cold air in coming in takes it up again. In the engines of the Ericsson the air which comes out is but 30° hotter than the atmosphere, though before passing through the wires it was 384° hotter. Even these 30o might be saved, says Captain Ericsson, by increasing the number of wire disks; but it is practically unnecessary. This apparatus is called the regenerator. Though the principle of it is essentially the same as that of Davy’s Safety Lamp, the glory of its application to mechanical purposes is Captain Ericsson’s forever.

As we said, there are four of these double cylinders, four working and four supply. Accordingly there are four furnaces, ingeniously arranged, and set without any extraordinary outlay of brick, such as hams been reported. In these a small fire is kept up with anthracite coal, which is preferable to other fuel, because it does not blaze—only its radiating heat is employed. From the grate to the apex of the cylinder-bottom, which is arched of course, there is a distance of five feet.

The cylinder-bottom is 1½ inches think. Before the engine is put in mot ion it may get to a brown heat, but at that distance it cannot get hotter. As soon as the cold air is let in, it cools much below that point. Thus there is no danger either of fusion, cracking, or oxydizing of the cylinder-bottom, all of which have been predicted by the sceptical. A cylinder-bottom will last five years, as long as a steam boiler; or if it gives out, can be easily replaced. The difference in the cost of replacing cylinder-bottoms and steam-boilers would, in a large ship, be from thirty to forty thousand dollars in favor of the former.

The piston in the working cylinder is made six feet deep from top to bottom, concave underneath to fit the cylinder-bottom, and flat at the top. The top as well as the sides are of iron, but the space between is filled with gypsum and charcoal, non-conductors of heat. Thus while the bottom has the temperature of the hot air in the cylinder, the top is perfectly cool. The heat there is barely sufficient to keep the tallow used for lubrication in a fluid state, not to burn it. In fact one can stand upon it as it plays up and down, and many gentlemen amused themselves yesterday by riding there. This enables the engineer at any time to grease just the part of it which he may desire; when the ship is careening for instance, and the friction of the piston is all on one side, that side can be directly lubricated. This is a point of great practical importance, which cannot be attained in a steam engine. Nor is there any danger of burning the packing, for it is at the top of the piston, and never comes within less than six feet of the fire.

The cylinders act in pairs, and in each pair the action is reciprocating; that is to say, as the piston goes up in one, it goes down in the other.

The pressure for which the caloric engine is calculated, is 12 lbs. per square inch; and to obtain this it is necessary to heat the air to 384°. By raising the air to 450o, a pressure of 15 lbs. could be obtained, but 12 is sufficient for practical purposes, and more convenient to manage. Capt. Ericsson is of opinion that that will be retained as the maximum pressure by future builders of engines.

Yesterday, owing to the unfinished state of the machine, and especially of the valves, it was impossible to get more than 8 lbs. pressure. With that, nine or ten revolutions were obtained per minute. The full number of revolutions to be had from the Ericsson’s engines is reckoned at 12, and at that rate it is calculated that she will make from ten to twelve miles an hour. This is the utmost that is hoped from her, and we think rather more than will be obtained. Her engines are not powerful enough to make her a competitor in speed with the fast Collins or Cunard steamers. For that she must have larger cylinders.

The means of increasing power is to enlarge the diameter of the cylinders. When these engines were built, Capt. Ericsson desired to have cylinders of sixteen feet, but no establishment would undertake to cast them, and fourteen were the largest he could get. Now, Messrs. Hogg & Delamater are ready to make them of any size required, at their own risk.

The smoothness with which the engines worked was remarkable. Captain Ericsson said that ½ lb. pressure was enough to move them. The amount of friction he finds very much less than he anticipated. The coal consumed by the whole four furnaces is at the rate of six tons in twenty-four hours; seven tons is the utmost limit of their consumption. The engineer and one fireman suffice to tend the whole mechanism. There is no unpleasant smell as about steam machinery. There are two smoke pipes and two pipes to carry off the escaped air.

These pipes are twelve feet above the deck and thirty inches in diameter. They are painted white, with a gilt rim at the top; but there is not smoke enough to sully them. The amount of air passing through the four cylinders in an hour is from fifty to seventy-five tons. This keeps the ship perfectly ventilated. It was cool and pleasant in the immediate vicinity of the furnaces.

The Ericsson is a beautiful ship as she sets on the water; a lovelier model one would not wish to see. She is 260 feet long on deck; 40 feet beam; depth of hold 27; diameter of wheel 32 feet; length of buckets 10½. With ballast in her, as at present, she draws 17 feet water. Her bottom is moderately sharp, and she is one of the strongest vessels in the port. The hull was built by Messrs. Perrine, Patterson & Stack, of Williamsburgh, and the engines by several builders, under the oversight of Capt. Ericsson himself.

It is not necessary here to add any reflections on the consequences to flow from this great invention. As we have already said, we do not think the Ericsson will prove a fast ship. But the new motive power is as well established with nine miles an hour as with ninety. Larger cylinders will be put into other ships, and speed will be attained which will leave steam as much behind as it is now surpassed in economy, safety, and convenience.

In this mighty revolution, the palm of honor belongs to the inventor; but no little credit is due to the gentlemen who have joined him in bringing out the caloric engine on such a scale, prominent among whom we may name Messrs. Edwin W. Stoughton and John B. Kitching. Nor do we desire to conceal a satisfaction which our countrymen will universally feel, that the new motive power has been brought out in the United States.