393 Mr. J. W. L. Glaisher on some new Facts in 



maseyu/ The negligence of a bookbinder enables us to clear 

 np some confusion in rather a singular manner. Sherwin states 

 that he examined his Table by one of Vlacq'Sj in large octavo, 

 printed at Gouda in 1636_, of which Table we find no other men- 

 tion. The Table before us corresponds in every respect except 

 that there is no author^s name; bat no one except Vlacq can be 

 mentioned who was in the least likely to have printed logarithms 

 at Gouda in or about 1626. At one time we thought that this 

 Table was the original of the long series of small Tables called 

 after Vlacq; but this was a mistake (see 16.25* Gellibrand), and 

 the mistake was partly due to the following circumstances. This 

 Table (Gouda_, 1626), having the title, when not cut away, above 

 described, and which we have also seen with a Dutch title and 

 preface, is the Table which is always bound up at the end of the 

 ' Sciographia, or art of Shadowes .... by T.f W[ells], Esq.^ 



London, 1635, large octavo That the book was intended 



to have these logarithms bound at the end is evident from every 

 page of it. Now the fact stands as follows : — A sufficient num- 

 ber of copies of the logarithms having been procured from 

 abroad, the binder was directed to cancel the title-page of the 

 logarithms, and to append them to the work. Accordingly most 

 copies have no title to the logarithms, which look quite like part 

 of the work. But in some copies the binder has not cancelled 

 as required : we have obtained two (since our first article was 

 written) ; and there is another in the library of the Royal Society. 

 But in all three copies the title of the logarithms is cut halfway 

 up with knife or scissors as a direction to the binder to cancel it. 

 One of our copies has the Dutch title-page to the Table, ^ Hen- 

 rici Briggii Tafel van Logarithmi voor de Ghetallen van een tot 



10000." Ter Goude 1626.' And the work (though the 



same impression as before) has a difi'erent title-page and date, 

 namely, ^The Compleat Art of Dyalling . . . , by T. Wells of 

 Deptford, Esq.' London, 1637.'' 



While preparing the Report of the British-iVssociation Com- 

 mittee on mathematical Tables, a copy of the original Dutch 

 edition of the above Table came to light in the library of the 

 Royal Observatory at Greenwich ; and 1 was not a little surprised 

 to find that it bore the name of Decker on the title-page, Vlacq 

 being only incidentally referred to in the preface. The full title 

 of this work, the copy of which (novf before me) must be almost 

 unique, is ^^ Nieuwe Telkonst, inhoudende de Logarithmi voor de 

 Ghetallen beginnende van ] tot 10000, ghemaeckt van Henrico 

 Briggio Professor van de Geometric tot Ocxfort. mitsgaders de 



* This a misprint for 1635. 



t It should be I. W[ells]: the initials on the title-page are I. V/.; and 

 the preface is signed J. W. 



