I thank you, most excellent Sir, for the exact description of your new and really harmonious harpsichord with glasses, which you have sent me (to you it is given to enlighten human minds with the true principles of the electric science, to reassure them by your conductors against the terrors of thunder, and to sweeten their senses with a most touching and suave music); and if I were entitled to it I would thank you, in the name of Italy, for having given the appellation of armonica to your agreeable instrument, in consideration of our harmonious language. So far as I am concerned, I do not know how better to show you my gratitude for the many other marks of your kindness, than by sending to you this new product of my labor, and accompanying it with the wish that it may still be in keeping with your first opinion of it, as you were pleased to express it.

As for the length of this volume, I hope it will not tire you; for, apart from the common excuse that I have not had time enough to write with more brevity, I have preferred to reply rather than to repeat myself whenever a reply would serve to make the subject more clearly understood; and to tell the truth, I do not think that the quantity of the material that is assembled and simplified is disproportionate to the size of the work.

Nor will you be surprised that I conclude this book, too, with expressing the hope of having added further definitions to the theory; for you too teach well, by your example, how slowly and how little our senses proceed in the investigation of every little parcel of inexhaustible Nature. And how many refinements does not a science, however comprehensive, still lack today? We measure the paths of light, yet we do not know how it proceeds through them. We can define the order of the system of the world, yet we do not know the force which links its parts in a most divine way, etc.

But what would happen if further definitions of electrical matters produced another, different theory? The appearance of all that I have so far been able to see takes any such suspicion from my mind; still, even in such a case, the value of these works of mine, if indeed they have any, would subsist. The experimental data would remain the same; their connection and unity, far from crumbling, would improve.

I hear that you are preparing to go back to your country. Whether America or Europe possess you, preserve yourself to the world, to science, and the lovers of it. Wherever you may be, I shall always be the most devoted admirer of your great merit, etc.