ponderous objects, and pass them to and fro through the rolls with the utmost case, -- to the great saving of heat, time, and labour. The invention was first brought into use by Mr. Ramsbotham at the Crewe works of the London and North-Western Railway. On the 4th December 1866 I received the following letter from him:

"DEAR SIR -- I must crave your forgiveness for my great delay in acknowledging the receipt of your kind letter of the 29th August, in which you refer to the successful carrying out at these works of your idea of a 'Reversible Rolling Mill without a Fly-wheel.' It has long been to me a matter of astonishment that your idea has not been reduced to practice years ago, particularly when it is considered how well the arrangement is adapted to the rolling of Armour Plates, or other work requiring a sustained effort, whilst it is at the same time more effective than the ordinary mill arrangement for very light work. So much is this latter true, that the men who are left to their own choice in the matter, will reverse the mill rather than pass a light sheet of 8 or 10 lbs. weight over the upper roll. This country is much indebted to you for so valuable a suggestion; and now that it has been brought to a successful issue, I have no doubt but it will be widely acted upon. I need not add that it will afford me much pleasure to show you the mill, and also what we are doing generally, if you should at any time visit Crewe. -- Believe me very faithfully yours, " J. RAMSBOTHAM."

I also communicated the invention to Mr. Thomas Gillott of the Farnley Ironworks, Yorkshire, and received from him the following letter, dated the 2d January 1877 :

" DEAR SIR -- I was much gratified to see by your letter in Engineering the interest you have shown with respect to the large Reversing Plate Mill erected by me at these works, and drawn on the plan suggested by you. Allow me to thank you for the complimentary manner in which you have mentioned my work. Since the notice appeared, we have done a deal of heavy work in this mill; and a plate large enough to shear 11' 0" and 10' 2" and 1/2" thick has been rolled in five minutes. The slab went through the roll 17 times before being rolled to the width and turned round, and 18 times after turning and of the full width; making a total of 35 passes -- the turning occupying 20 seconds. When it is remembered how rapidly a thin plate cools, this performance will sufficiently indicate the severe work this mill is capable of doing; notwithstanding the many predictions that such large plates could not be rolled without a fly-wheel. As to repairs, none have been required; so I cannot compare this with the Clutch systems. In respect of steam used, the direct acting engines compare favourably with an expansion beam condensing engine doing similar but lighter work. Should it ever be your wish to see this mill at work, I should be much pleased to have the opportunity of showing it to you. -- I am, dear sir, your obedient servant,

"THOMAS GILLOTT."

Drilling Tunnels through Hard Rock.

Besides these contrivances and methods of accomplishing mechanical objects, I have on several occasions read papers, prepared drawings, and given suggestions, out of which have come so-called "inventions" made by others. For instance, at the meeting of the British Association in Liverpool in 1854, I read a paper and exhibited drawings before the Mechanical Science Section, on my method of drilling tunnels through hard rock. The paper and drawings excited considerable interest among the railway engineers who were present. I afterwards met Mr. George Newmann, C.E., who consulted me on the same subject. Several years after (21st April 1863) I received the following letter from him:

"DEAR Sir -- Some few years ago, I had the pleasure of spending an evening in your company at my relative's (Mr. G. Withington) house at Pendleton. As I was then Engineer to the Victor Emmanuel Railway, and had made a survey of the Mout Cenis for the purpose of the Tunnel, I consulted you as to the application of the machinery for that work. You suggested the driving of drills in a manner similar to a piston-rod, with other details. On my return to Savoy, I communicated these ideas to Mr. Bartlett, the contractor's agent, and I recommended him to get a small trial machine made. This he had done in a few months, and then he claimed the whole idea as his own. The system has since been carried out (see Times,