391 
prietas et similitudinis gratia, quia me Hercule novas tabulas 
introducis, et uno ictu liberas computatores debitis multiplicandi, 
et dividendi inextricabilibus” But he hopes that this title will 
not offend Maginus on account of his ‘Tabula tetragonica’ 
[Venice, 1592]. At the end he adds the postscript, “ Titulus 
igitur talis: YevoayGeva, sive Nove Tabule, quibus Arithmetict 
debitis inextricabilibus multiplicandi et dividendi lberantur, 
ingenis, tempori, viribusque ratiocinantis consulitur.” 
It is thus proved that the table was printed from a manu- 
script which Herwart used himself, and which very likely he 
had had made. The correspondence is of interest, as the 
table, regarded simply as a multiplication table, has never 
been surpassed in extent, and has only been equalled by 
Crelle’s Rechentafeln, first published in 1820, in two volumes, 
and which, now sold in one volume folio, is one of the best 
known and most used tables. Scheibel and others who have 
ridiculed Herwart’s project were only right in so far as the 
great size of the work renders it unmanageable, as the use of 
a multiplication table up to 1000 x 1000 has, in spite of loga- 
rithms, been found to be both practicable and convenient. 
Herwart’s work is very rare, but there are copies in the 
British Museum, the Bodleian Library, and the Graves Library 
at University College, London. It was this last (not quite 
perfect) copy which, through the kindness of Professor Henrici, 
I was enabled to exhibit to the meeting. 
With regard to the word prosthapheeresis, it 1s well known 
that the prosthapheresis of the orbit was the angle subtended 
by the eccentricity at the planet, and De Morgan explained 
the use of the word on the title-page thus: “Prosthapheresis is 
a word compounded of prosthesis and apheresis, and means 
addition and subtraction. Astronomical corrections, sometimes 
additive and sometimes subtractive, were called prosthaphere- 
ses. The constant necessity for multiplication in forming pro- 
portional parts for the corrections, gave rise to this table, which 
