jury.

Parke, B., to the continued to manage with them for two or three years. Then we got the water twires afterwards." Therefore, according to his account, they used two cylinders, not a very improved apparatus, but a tolerably simple one. They succeeded in producing, if you believe him, a very great degree of heat, probably at least 400 degrees; and also they contrived to get on with dry twires, without introducing water twires at all, or any other substitute for ordinary dry twires, more capable of resisting the heat than they are. If you believe that evidence, and place entire reliance upon it, it would show that the omission of introducing twires into the specification was a circumstance that was not material to the validity of the patent. "They used this method," he says, "without intermission in 1837, when I left." He says "I have read the specification. I think that no one acquainted with the making of iron would have any difficulty in constructing an apparatus from it." Then he says " Mr. Neilson sent a man and a plan. The first apparatus was erected with the assistance of the man. The vessel which was put up was a cylinder made of malleable iron, thirtyfour feet in its cubical contents. It was heated by a fire under it. The flame passed round it. It was enclosed in brick-work. It had four half partitions in it to drive the air against the sides. The partitions were connected with the outside, the object being to retard it, and drive it on the sides. That box was sent from Glasgow. We then put up a second machine in two or three days; I cannot say whether is was part of the original plan, or whether it was sent for to Glasgow." Probably it was a part of the original plan, because it was sent in two or three days; he could not tell, however, how long such an instrument would be in constructing. He says "The second plan was a cylinder, made bottle-necked at the end, without partitions." So far as we learn from this evidence, it appears pretty clearly that he was not acquainted by any means with the full benefit of his invention. If he had known that the tubular form would answer best, he ought to have introduced it, and the specification would have been bad, upon the ground that he concealed the best mode of working out his own discovery. However, I think one may very well collect from the evidence as to Mr. Neilson's own acts, that he really was not fully aware either of the great value of his patent, and still more, was not fully aware of the most beneficial mode of carrying it into effect. That was discovered by persons more acquainted than he himself was The patent is with the science of heating air. Still, however, I think, if you not void by rea- are of opinion that the specification does disclose such an son of the apparatus described apparatus as to enable an ordinary workman, acquainted with admitting of the the subject of making blowing apparatus, and fitting up appa

greatest improvements.

ratus for forges, to construct an apparatus of some value, so as to make it worth while, it seems to me, that so far as this objec

tion goes, the specification would not be insufficient. He says- A.D. 1841. "The next was a serpentine pipe, twelve feet long, nine and a half feet in a straight line." I need not go through the various variations that took place afterwards in the progress of the improvements. Ultimately they got to small tubes, then there was some gridiron pipe used in 1832, and the tubular form was adopted; and there can be no question that that was the most beneficial form as far as experience goes to this time. He says "We found the old dry twires answer to a certain extent. Sometimes they lasted a week or more, or a few days; sometimes a few hours." He says "They were removed oftener than with the cold blast. It frequently happened that they lasted only a few hours. They were changed oftener than once a week, sometimes two or three times a week. They were not changed in the furnace; not once a day. I should say there might be one a day in both furnaces. Sometimes the blast stopped for a quarter of an hour, sometimes half an hour, or an hour. It generally takes two or three people to do it. In some cases two twires have been put in in one day. I cannot say it has not happened that four or five twires have not been put in in one day. Before I went there, I had no experience in smelting iron. I was the underground surveyor, and made the plans for the works, and had free access to the works, and the books. I made myself well acquainted with what was going on, so as to be enabled to say that it was worked to a profit. In 1831," he says, "a range of horizontal pipes were introduced; there was a continual flow of air from the pipes; that raised the temperature to as great a degree of heat as ever has been "We used a variety of forms of vessels in different furnaces at the same time."

acquired since." He says

Mr. Farey says "I have investigated the subject of iron smelting. I have known the mode in which iron is smelted for thirty or forty years. Cold blast was used for smelting iron before the hot blast was employed. It is a new invention of Mr. Neilson's, and contrary to the opinion which was universally entertained, that the colder the air the better. The heat was considered as inimical. I consider this as an invention of very great magnitude indeed, applicable to all smelting operations where the blast is used. It will soon," he says, “in all probability, be used as a substitution for reverberating furnaces." He says "A person acquainted with a blowing apparatus as it existed before the discovery, and as it exists still, would have no difficulty in constructing an apparatus for the improved application of air to a beneficial extent—I mean, accustomed to the construction of blowing machinery. Those are of a high class, and have all the requisite knowledge for adopting this improvement." Now, what he goes on to state afterwards seems to render it doubtful, whether an ordinary

Parke, B., to the person would be able to do it; but if the simplest form would jury. be a benefit, one should not feel much difficulty in saying that he would be able to work out a beneficial apparatus from this specification. "I am acquainted," he says, "with the mode of constructing vessels for heating air. The object is to get the largest surface exposed to the fire. There are two qualifications; the first is, that there should be a sufficient passage in the vessel, so as to allow the current of air to pass without obstruction; and the other is, that the air in its passage shall be compelled to pass in contact with the heated surface; and with these two conditions the form and shape are immaterial.” That part will be material for you to attend to (n). "The size depends upon the quantity of blast required, and the temperature to which it is heated. These principles were well known at the date of the patent. I knew of water twires in 1809." Then he describes the three descriptions of water twires which have been used, and are now used. And on cross-examination, in order to ascertain what he meant by a high class of engineers, he said "He considered Watt and all manufacturers of steam engines and blowing engines of the first class." He says "They have very scientific men in their employ. I think an engineer of the second class would construct an apparatus which would be beneficial; but not to the extent to which it has now reached, or would reach, in the hands of that class exclusively employed in making blowing apparatus.' He says "The third class are iron masters, making their own apparatus; they would do it," he says, "beneficially; not so good as the second, and not near so good as the first. An ordinary workman would not be employed by an engineer of the first or third class. A man must bring the ordinary information which is current among those who are employed to design and construct blowing apparatus. One of the points is to provide an adequate passage for the air. The rules and proportions for such passages are well known and habitually practised; he must also possess and exercise that knowledge in the application of fire to heat boilers, which is equally well known and habitually practised in the making of steam engines. He must also pay atten tion to the circumstance that the contact of the air must be kept pretty constant to the surface of the vessel, and upon that subject the specification contains very useful information, stating the capacity for a common cupola." Then there is a question as to the rules and proportions. "The passage of the

(n) Sir W. Follett, on the part of the plaintiffs, called the learned judge's attention to the notice of objections, and contended that the supposed misstatement contained in the words "the form or shape of the vessel is immaterial to the effect," was not pointed out in the notice of objections.

"

But the learned judge being of opinion, though not specifically pointed out, it was included in the general words of the notice, "that the specification is calculated to deceive," leave was given to move upon that point.

pipe to contain the air should not be less than one-sixteenth of A.D. 1841. the blowing piston, or one-fourth of the diameter; he may make it larger if he pleases-that is the ordinary rule for blowing apparatus, so that the air would pass sixteen times as fast as the piston travels. If the passages are made larger, it goes slower, with less obstruction. There is no objection to make it larger; but it ought not to be smaller that is all I have to say as to the passage of air." Then he says "It might be made so large that the heating of air would not take place. As to the steam vessel, the great object is to distribute the heat all over the surface, so that it would not be too vehement in a particular part and destroy the boiler. The object ought to be, that the heat should be retained in contact with the boiler so long, that there is no extravagant waste of heat passing up the chimney." That is speaking of the steam apparatus. These are the two points to be accomplished. He says "An engineer of the third class would not be so competent by reason of want of science, and the inferior work which they copy. An engineer of the third class would have no difficulty, if the thing was described to him; he would be in a situation of having a copy go by, and without that he thinks that he still could make an apparatus which would be useful." He says " Assuming the size to be given, the form and shape are immaterial, provided you attend to the two conditions." It was a long while before we could get him to state the exact fact as to that. This question was put to him-"Supposing ten thousand cubic inches are required, is it immaterial whether it is a tube, a globe, a cylinder, a pipe, or an elongated cylinder?" He says"No; it is very material-the variance of the shape is very material, unless my conditions are attended to, the conditions under which the air is to be supplied." This specification says that the shape is immaterial to the effect, whereas all the effect depends upon the shape of the vessel; and unless that can be controlled by the admission of the evidence of a person acquainted with the subject, and that evidence is to you satisfactory, I am afraid, according to my present opinion (it may be possibly wrong), that the patent has failed.

Mr. Holdsworth, an iron master, says "A person acquainted with the mode of constructing a blowing apparatus would have no difficulty in constructing a proper apparatus from the specification. We have only three furnaces in operation. We have at several times varied the form. The new plan is to make the pipes longer, with an oven over them, so as to make the temperature more uniform." He says-" I read the specification to see whether it was a good patent. I am a cotton spinner, a machine maker, and an iron founder. The box or cylinder would no doubt heat the air to a certain temperature-what temperature I cannot say. I differ with Mr. Farey as to some

Parke, B., to the parts of his evidence. I consider that any form of vessel would jury. heat the air. I think it might be heated in a cubical box without partitions in it quite easily. Any one would try the simplest and easiest plan to see how it would answer." That If experiment be would be experiment; and if experiment were necessary in necessary, the order to make it answer in all the three cases, then it would not specification is bad. be a good specification. If experiments were necessary, and a man could not do it with the means and knowledge which he possessed, and it were necessary to make experiments in order that the plan should answer in all the three cases, if that were the case, the patent would be void upon the substantial ground. "I agree that to a great heat the shape is material, but to heat the air it is immaterial. The form and shape are immaterial in this, that any vessel will produce a result; the form and shape are material as to the extent of the beneficial result. The last shape is the horse-shoe form, which gives 600 degrees. The last improvement is increasing the heated surface in proportion to the air to be heated."

Then Mr. Kirkman, an engineer, says "I had the specification put into my hands. I was requested to make experiments, so as to speak to it. I prepared no apparatus. Finding two gas retorts about the works, I put them up. They were thirteen inches and a-half in diameter, and in length four feet nine inches, and the contents were 18,000 cubic inches. I found upon an experiment that it was beneficial to this extent, that with cold air we required 298 lbs. of coke to melt a ton of iron, and that with this apparatus and the hot blast I found it was reduced to 113 lbs., which is a saving of one-half in the fuel." He says "I required no other directions than those in the specification, added to my own practical knowledge. I employed one cylinder, which we worked up to 315 and 480 degrees. There was a very considerable saving. Any person accustomed to manufacture apparatus of this kind would find no difficulty."

Then, Professor Daniel says "I am acquainted with the specification. I never knew of the hot blast before. A person accustomed to the manufacture of blowing apparatus, would be able to make a beneficial apparatus according to the specification, and most clearly a person accustomed to the process of heating air, and better acquainted with the principle and nature of the invention, would construct a beneficial apparatus. The principle is entirely new; I never saw the process in actual operation. The shape depends upon circumstances--the situation, the heat required, and the power of the blowing apparatus."

Mr. Cooper says "Looking at the specification, there would be no difficulty in heating the air to a certain extent, so as to use it beneficially, but there would be some difficulty as to obtaining the best mode. I do not believe that has yet been done." And he thinks it probable that improvements will take