NAPIER COMMEMORATIVE LECTURE. 69 
responsibility for this great task fell to the former. So 
eagerly did he set himself to the work that in 1617 he was 
able to publish the logarithms of the first 1,000 numbers 
(Logarithmorum Chilias prima, London, 1617). In 1620 
Gunter published in London tables of the logarithms of 
sines and tangents for every minute to seven decimals. 
In 1624 Briggs followed his earlier work by the Arithmetica 
Logarithmica, in which the logarithms of all numbers from 
1 to 20,000 and 90,000 to 100,000 are given to 14 places. 
A specimen of these tables is given below. 
Briggs’ Table of Logarithms (1624). 
Numeri | Numeri 
absoluti. Logarithmi absoluti Logarithm 
16501 | 4,21751,02642,9403 | 16534 
2,63184,8511 
16502 | 4,21753,65827,7914 
2,63168,9029 
16503 | 4,21756,28996,6943 
| 2,63152,9567 
It will be seen that Briggs takes log 10 = 1, and that 
we have now to deal with decimal fractions in the ordinary 
way. Napier, by choosing 10,000,000,000 as the logarithm 
of 10, practically obtained these logarithms on the usual 
scale to ten places. While Briggs was busily engaged in 
completing his Tables, calculating the logarithms of the 
numbers from 20,000 to 90,000 to fourteen places, he was 
anticipated by a Dutchman, Vlacq, who in 1628 published 
an Arithmetica Logarithmica, which he called a second 
edition of Briggs’ work of the same name. This contained 
the logarithms of all numbers from 1 to 100,000, calculated 
to ten places of decimals. In addition, it included the 
logarithms of the usual six trigonometrical functions for 
every minute, to the same number of places. A specimen 
of the tables is given on the next page :— 
