“Such in substance is our verbal understanding. But as I am about to leave England, it becomes proper, for more reasons than one, that we should make a memorandum of agreement in writing, to the end of making it good in law and binding also upon our heirs and assigns. With this view, this writing is drawn and the following statement is added. The points upon which this system hangs and which give special value to the information imparted to you concerning it are mainly these: 1. A plan for determining by cross bearings when the enemy is in the torpedo field of destruction and for ‘making connections’ among the torpedo wires in a certain way and by which the concurrence of each of two operators becomes necessary for the explosion of any one or more torpedoes. This plan requires each operator to be so placed or stationed that a line drawn straight from them to the place of the torpedoes may intersect as nearly as practicable at right angles. And it requires the connection to be such that each operator may put his station in or out of circuit at will. When the torpedoes are laid, a range for each station is established for every torpedo or group of torpedoes. When either operator observes an enemy in range with any torpedo, he closes his circuit for that torpedo. If the enemy before getting out of this range should enter the range for any torpedo from the other station, the operator there closes his circuit and discharges the igniting spark. Consequently, if the ranges belong to the same torpedo, its explosion takes place. But if not, there will be no explosion. Hence, here is an artifice by which explosion becomes impossible when the enemy is not in the field of destruction and sure when she is. 2. The Electrical Gauge, a contrivance of my own which you perfectly understand and some of which you have already made; by means of it one of the tests which the igniting fuse has to undergo before it is accepted is applied. By means of it, the operators can telegraph through the fuse to each other without risk to the torpedoes and by which the torpedoes may without detriment to their explosibility be tested daily or as often as required. And thus the operators can at all times make sure that all is right. 3. A plan for planting torpedoes where the water is too deep for them to lie on the bottom and explode with effect, by which they will not interfere with the navigation of the channels and by which, when the enemy makes his appearance, they may by the touch of a key be brought instantly into the required position at the required depth. These contrivances are very simple. They are readily understood from verbal description. They require neither models nor drawings for illustration. You understand them all. They are of little or no value except to governments and, as against these letters of patent are of no use, I have not deemed letters patent desirable. I have every confidence in you and therefore intrust the