64 | H. S. CARSLAW. 
and better system of logarithms could be substituted for 
Napier’s original system. He visited Napier at Merchiston 
in 1615 and 1616, and was preparing to visit him again in 
1617, when news of his death arrived. With the subsequent 
history of logarithms the names of Napier and Briggs are 
most intimately associated. 
Briggs’ account of the matter is given in his Arithmetica 
Logarithmica (1624) :— 
“JT myself, when expounding publicly in London their doctrine 
to my auditors in Gresham College, remarked that it would be 
much more convenient that 0 should stand for the logarithm of 
the whole sine, as in the Canon Mirificus, but that the logarithm 
of the tenth part of the whole sine, that is to say, 5 degrees 44 
minutes 21 seconds, should be 10,000,000,000. Concerning that 
matter I wrote immediately to the author himself; and as soon as 
the season of the year and the vacation time of my public duties 
of instruction permitted, I took journey to Edinburgh, where, 
being most hospitably received by him, I lingered for a whole 
month. But as we held discourse concerning this change in the 
system of logarithms, he said that for a long time he had been 
sensible of the same thing, and had been anxious to accomplish 
it, but that he had published those he had already prepared, until 
he could construct tables more convenient, if other weighty 
matters and his frail health would permit him so todo. But he 
conceived that the change ought to be affected in this manner, 
that 0 should become the logarithm of unity, and 10,000,000,000 
that of the whole sine; which I could not but admit was by far the 
most convenient of all. So, rejecting those which I had already 
prepared, I commenced, under his encouraging counsel, to ponder 
seriously about the calculation of these tables.” 
Napier himself, in several places in the original edition’ 
of the Descriptio, and again, in more exact terms in a note 
in Wright’s English translation, refers to modifications 
which he proposed to make in the original system. He 
