quently thereby more quickly withdrawn from the condenser. Previously to setting the engine to work, it is necessary to withdraw the air from the condenser and vapour cylinder, which is done by means of an exhausting pump or syringe applied at c, to a pipe with a stop-cock b, fixed on the top of the condenser. The liquid to be converted into vapour for working the engine, is introduced into the vessel or reservoir at the bottom of the condenser, through a tube e, closed by a screw cap f. From this vessel or reservoir (the fluid in the cylinder having been first heated,) the liquid is thrown into the cylinder A by the forcing pump R, as before described. A mercurial gauge may be fixed in the usual manner to any part of the condenser, in order to show the degree of exhaustion within. This method of producing condensation, consists in exposing the vapour or elastic fluid to be condensed, to a large surface of metal, surrounded or covered with flannel, or some other porous substance, continually absorbing water, and at the same time acted on by a stream of atmospheric air. And I claim the application of this new method of producing the condensation of the elastic fluids or vapour, as applicable generally, and not as applicable to my engine only. The condensation of the vapour or elastic fluid, may also be effected by injection upon the same principle as in the steam engine, but with the advantage of dispensing with the constant use of an air pump, and effectually preventing the escape of any of the vapour, or liquid. To effect the condensation by injection, a tube S, (drawing No. 2,) conveys the vapour into an oblong vessel g, made of copper or other metal, as thin as the pressure will allow. The required quantity of the liquid before mentioned, and to be afterwards thrown into the cylinder, is introduced into the condenser or vessel g, by the tube e as before, or by a funnel o on the top through a stop cock

The forcing pump R, the tube E, to convey the liquid into the cylinder, the pipe and cock b, for withdrawing the air, and also the pipe and cock d, by which the liquid may at any time be withdrawn, are constructed as in the hereinbefore described condenser, and answer the like purposes. A lifting pump h is put in motion by the engine; at the same time the valve in the vapour cylinder (G, in the drawing No. 1,) is opened as hereinbefore described, and the lifting pump withdrawing a quantity of the liquid before mentioned from the bottom of the vessel or condenser g, injects it into the top of the same vessel after passing it through a pipe or worm, i, the end k, of which pipe being pierced with many small holes, the liquid is dispersed throughout the vessel g, and condensing the vapour therein, passes with it to the bottom of the vessel. Part of this liquid is again thrown into the cylinder by the forcing pump R, to be converted into vapour as before described, and part of it is again employed to condense the vapour in the manner last before mentioned. In effecting the condensation by injection, the condenser and tubes connected therewith are immersed in a cistern of cold water, a stream of which is continually passing through it, as in the steam engine. The vapour engine hereinbefore described, operates against the pressure of the atmosphere. This may be avoided, and a double

action produced by the following alterations: (the Specification then proceeds to describe them.)

Although I prefer the use of lamps upon Argand's principle, in order to obtain the requisite degree of heat, to give motion to my vapour engine; yet, an engine inay be so constructed that fuel of any kind may be used. The foregoing are some of the combinations of machinery to which my invention is applicable, but I moreover claim, as my exclusive invention, the application for the purpose of giving motion to machinery, of vapour generated from liquids within the cylinder or other vessel, in which the power operates, the vapour receiving an increase of expansive power by the heat of the said vessel; particularly when the vapour is generated from such liquids as evaporate at a lower temperature than water.

THOS. HOWARD.

The annexed drawing describes an engine, which operates against the pressure of the atmosphere, and upon which also depends the return or vacuum stroke of the piston. Two methods of avoiding this and producing a double action, are given in the specification, but which are not inserted here. The following diagram presents an outline of a very effectual arrangement. a a are the vapour cylinders or vessels (the form of which may be varied;) b is the piston cylinder; e the piston, working horizontally. The arrangement of the lamps, injecting tubes, &c. is upon the same principle as before. The vapour is alternately generated within, and withdrawn from the two vessels, a a, and acts upon the piston through the

a

d

medium of the oil or other fluid, upon which, or upon the thin copper floats, dd, the small quantity of liquid to be evaporated is injected, as before described.

Remarks by the Patentec.*-I have denominated my invention a "Vapour Engine," because the vapour of certain liquids, other than water, may be advantageously employed, the term steam being more properly applied to an engine which is worked exclusively with the vapour of water.

When the idea first occurred to me of employing, instead of water, liquids which evaporate at a lower temperature, I perceived, immediately, that it would be hopeless to attempt the practice of such a theory upon the present principle of the steam engine; and when I afterwards found that such had actually been attempted with alcohol, I was not surprised that it had proved abortive. To say nothing of the danger of placing a furnace under a boiler containing a large quantity of an inflammable liquid, it would be almost impossible to

Of these remarks we have abstracted a small part only, and that, not so much with the design of showing the views of the patentee, as of exhibiting the principle upon which the anticipated advantages of vapour engines generally is founded.

EDITOR,

prevent its escape, which would soon amount to far more than the saving of fuel that would be made upon that plan. After making many experiments, it appeared to me that the vapour might, by a new and proper arrangement, be generated within the cylinder itself, and thus do away with the necessity of a separate boiler or generator of any kind. I ascertained that ether or alcohol would evaporate with sufficient rapidity, and would produce an instantaneous and very great pressure in a closed vessel, if the surface upon which a small quantity was thrown were heated to about 100° above the boiling point of the liquid. In these experiments mercury was employed as a medium upon which to evaporate the liquid. The following table will explain the system.

and so on in proportion, for every additional 40° of heat, but gradually decreasing in effect as the temperature advances. The calculations are given only as an approximation sufficiently correct to illustrate the theory.

Suppose it be required to work an engine with ether, having a cylinder or vapour vessel or vessels, 20 inches in diameter and 30 inches in length, and with a pressure upon the piston, or (which is the same in effect) upon the intermediate fluid, of eight atmospheres, and which would be a very powerful engine. Such a vessel as that above described will contain about 10,000 cubic inches. This will require the evaporation of about 51, say 6, cubic inches of ether at 220°, and as 6 cubic inches contain nearly 1600 grains or drops of liquid, 5 drops must be evaporated from each square inch, since the diameter of the vessel, 20 inches, presents a surface of about 320 square inches. Five drops of ether upon a square inch of surface heated to 220°, will evaporate with a rapidity sufficient to produce a motion equal at least to the condensing steam engine. By decreasing the heat or the quantity of liquid injected, the effect will be decreased in proportion, so that the motion and power of the engine may be governed with great exactness. If the quantity of liquid

* In a subsequent communication, the patentee states that this fifth column is incorrect; the scientific reader will make the same remark upon the fourth, in which, the force of vapour is made to double with every addition of 40° of heat; this is only an approximation. EDITOR

injected be decreased, and not the heat, the power (pressure) only will be decreased: the motion, so far as depends upon the quickness of evaporation, may even be increased. The relative proportion between the motion and power, also, depends upon that between the surface of the piston and the surface of the intermediate fluid, which receives the pressure of the vapour. It is not necessary at present to enter fully into this part of the subject; there must be, of course, a certain modification with regard to the temperature and the quantity of liquid injected, which must be found, by practice, to produce the most advantageous result; this will vary according to the purpose for which the engine is designed, and from other circumstances.

Alcohol will furnish the same results as ether, if the temperature be raised 75° higher; and upon the whole, this liquid may perhaps be preferable, particularly as it may be more readily and effectually

condensed.

Water will also give the same expansive power at 112° higher than ether, or $7° higher than alcohol; but the motion of the engine would be comparatively slow at this degree of heat, and, therefore, independently of the necessary increase of temperature, the greater quantity of latent caloric absorbed by its vapour, and other circumstances, the same effect can only be produced from this liquid by a greater consumption of fuel.

It is scarcely necessary for me to point out to those who are conversant with these subjects, the advantages which will result from the employment of the vapour engine, particularly in navigation. It is proper, however, that I should take some notice of them. The most apparent are, the very small consumption of fuel; the absence of all nuisance from smoke, and of a chimney flue, when lamps are made use of; the trifling space occupied by the quantity of oil, or other material, necessary, even for the longest voyage, compared with that at present required in steam vessels for the stowage of coal; the small space occupied by an engine of the greatest power; its perfect safety, portability, and moderate expense of construction.

Account of a patent granted to ARNOLD BUFFUM, late of Massachusetts, but now residing in the City of London, (being one of the people called Quakers,) Hat Manufacturer, in consequence of communications made to him by certain foreigners residing abroad, and discoveries made by himself, for an Invention of certain Improvements in the process of Making, or Manufacturing, and Dying Hats.

THE patentee states, that there are four principal objects accomplished by this invention; 1st, facilities in the process of dying hats; 2nd, the production of a more perfect colour; Sd, the prevention of any of the damages to which hats are subject in the common mode of dying; 4th, the accomplishment of the dying process in a much shorter time than by the usual methods, and of consequence lessen

ing the deleterious effects of the dying materials upon the hat itself, which frequently does great injury.

It is considered by the patentee, that the process of dying hats will be greatly facilitated, and the colour improved, by occasionally removing the hats from the dye vat or copper, and exposing them to the oxygen of the atmosphere; and it is also observed, that the colour of the hats suffers injury by touching the sides of the vat or copper in dying, and in being pressed against each other. In order, therefore, to remove the hats occasionally from the dye copper with convenience and facility, and at the same time prevent their being brought in contact while immersed in the dying liquor, an apparatus is proposed by which these objects may both be effected.

One method of constructing the apparatus is to make a vat, or dyekettle in the form of a half cylinder, with flat ends; within this, a hollow frame work wheel is made to revolve, like a grindstone in its trough; one half of this wheel, when placed upon the kettle, will be immersed in the dying liquor, and the other half exposed to the air. Within the rim of this wide wheel there are pegs upon which the hats to be dyed are placed, so that as it revolves they are successively passed into, and out of the dying liquor.

This wheel may either be kept revolving with a very slow motion, by gear connecting its axle to any moving power, or it may be turned half round at intervals of about ten minutes apart; by which means, the hats hung upon the pegs will be alternately immersed for the space of ten minutes in the dying liquor, and then for the same space exposed to the atmospheric air.

In this way it is considered that the process of dying hats may be greatly facilitated and improved, as the occasional transition from the dye vat into the air, and from the air again into the dye, will enable the oxygen of the atmosphere to strike the dye more perfectly and expeditiously into the materials of which the hat is composed, than by a continued immersion in the dye for a much greater length

of time.

A variation in the mode of performing this process, is suggested, and the apparatus proposed to be employed, is a square vat or vessel to contain the dying liquor; and a frame or rack having a number of pegs placed in it for hanging the hats upon, which are about to be dyed, in a similar manner to the wheel above described. This frame or rack is suspended by cords from a crane, and may in that way be lowered down with the hats into the vat, or drawn up and exposed to the atmosphere; which changes are recommended to be made every ten minutes until the dying is completed.

[Newton's Journal.

Account of a patent granted to JoHN ROTHWELL, Tape Manufacturer, for his Invention of an Improved Heald or Harness for Weaving. The object of the patentee, in the construction of these improved healds, or harness for guiding the warp threads in a loom, appears