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Algebra, and other branches of the Mathematicks and Mechanicks, for the use of those that are studious in those Noble Arts, as well to direct in the best Methods, and to detect Erroneous adventures, for the behoof of generous Beginners, as for the satisfaction and further encouragement of them that have attain'd higher accomplishments.
Also, in each of these Volumes, hath been given the Breviate and Substance of such Philosophical Writings, as came abroad, and were thought of good worth. And all along we have interspers'd many Histories, Philosophical Observations and promiscuous Experiments.
And now, I think, we may take our Prospect, and see, that we have got more ground in our second Volume than in the first and more yet in the third than in either of the former; whence we take the liberty to ominate well for the future. Yet in all that I assume nothing to my self, but give all what it due to the merits of my generous Correspondents. And all that have affection for Arts and Sciences may rejoyce to see the late Proficiency of the Ingenious and Nobler Students in both our famous Universities, and tn all the Universities of Christendom. The Ingenious French have drawn the same Yoke with us, in publishing their Journal des Scavans; and the Romans have followed our Example in their Giornale de Letterati. And doubtless all Civil Nations, who have a Gust for useful knowledge, will, in good time, drive on this Example; and then, as the Light increaseth, and runs on, we shall in a like proportion become so many mutual Ayds to each other: And that will hopefully redound to the General good of Mankind.
I doubt not but the Reader will pardon the Prolixity of this Preface, since, as was promis'd, it is not onely Preface, but bears a part of my main business, which is, to excite and animate the Industry and free Communications of others; of some of whole Effects take for the present the Specimens following.
The Description
SEe Fig. I. Wherein A. is a small Sight with a short arm B. which may be turn'd round about, and mov'd up and down the small Cylinder CD. which is screw'd into the piece ED. at D. this
