same size, viz. a 9th part to make up that Lesser Third a Fourth, we shall find that we have a great way over-shot the fourth part of the String, and without taking the 10th part, we can never hit it; as will appear by the former demonstrations upon the Monochord, in ma∣ny instances.
I must confess, this is so contrary to the common O∣pinion of Practical Musicians, that I would not insist up∣on it, did not necessity compel me, did not the greatest Reason and Authority assure me, that it will not be hereafter denied: Of these three sizes of Seconds does the whole progress, from the Key to the Octave, con∣sist in the forementioned order, being all along exactly coincident with the larger Intervals.
My Authorities are Cartes's Musick, Gassendus's In∣troduction, Wallis's Appendix, and all other Learned men, who have in this last Age reviewed the Harmoni∣cal concerns. 'Tis time certainly to receive into pra∣ctice those Improvements, which the greatest Modern Philosophers in the World have afforded Musick.
And indeed 'tis in vain to stand out, Nature always acknowledged and received them; a good Voice per∣forming by it self, a faithful Hand guided by a good Ear upon an unfretted unconfined Instrument, exactly ob∣serves them: All that I contend for is, that the Practi∣ser may know what he does, and may always make that his design, which is his excellency.
When we have thus much granted, then may the last Chapter of this Proposal be very acceptable; which puts into his hands the Tables of Proportions calculated for every Key, that he may perform them upon those Instruments, which have not hitherto been capable there∣of. But to pursue our present subject.