58 BJiroiiT — 1873. 



(or higher terms with any of the above denominators); it only appears as 5 ia 

 the 48 column. 



In reference to a work by Girtanuer (179-i) which we have not seen, but 

 which appears to be very similar to the present, De Morgan justl}'^ remarks, 

 " But it will not do : Mohammed must go to the mountain. When coin- 

 age, weights, and measures are decimalized, the use of logarithms will foUow 

 as a matter of course. It is useless trying to bring logarithms to ordinary 

 fractions." 



Rees's Cyclopaedia (Art. "Logarithms," vol. xxi.), 1819. Seven-ligure 

 logarithms of numbers from 1000 to 10,000, with differences ; arranged in 

 groups of five. 



Schron, 1838. Three-figure logarithms to 1400, and five-figure logarithms 

 to 14,000, with corresponding degrees, minutes, &c., and proportional parts. 

 Of the 20 pages 4 are occupied with explanations &c. The arrangement is as 

 in seven-figure tables. 



Steinberger, 1840. The titlepage is misleading ; the logarithms do not 

 extend from 1 to 1,000,000, but only from 1 to 10,000. The only pretext 

 for giving 1,000,000 as the limit is that, of course, two additional figures may 

 be obtained by interpolation ; but on this principle ordinary seven-figure 

 tables should be described as extending, not to 100,000, but to 10,000,000. 



The first five figures of the logarithms are printed in larger type than, and 

 separated by an interval from, the last two, so that the table may be more 

 conveniently used either as a five- or seven-figure table ; the change of 

 figure is denoted by an asterisk prefixed to all the logarithms affected. The 

 figures, though large, are not clear, the appearance of the page being dazzling ; 

 the 6's and 9's also seem too large for the other figures, and after all are not 

 very readily distinguishable from the O's. No differences or proportional 

 parts are given. 



Montferrier's Mathematical Dictionary, 1840. Under the Article 

 "Logarithmes," in t. iii. (the supplementary volume) is given a table of four-- 

 figure logarithms of numbers from 1000 to 10,000 (pp. 271-279). 



In the same volume (p. 2.52, facing letter L) is given a table of logarithms 

 of the numbers from 1 to 420 to base 2 to five places, the only table of th& 

 kind wo have met with. 



Babbage, 1841. Seven-figure logarithms of numbers from 1 to 1200 and 

 from 10,000 to 108,000, with diflferences and proportional parts (the last 

 8000 are given to 8 places). Degrees, minutes, and seconds are also added, 

 but they arc divided from the numbers by a thick black line, and are printed 

 in somewhat smaller type, so that they are not so obtrusive as in Callet and 

 others. On the last page there are a few constants. 



Great pains were taken Avith the preparation of this table (which is stereo- 

 type), with the view of ensuring the maximum of clearness &c., and -wdth 

 success. The change of figure in the middle of the block is marked by a 

 change in type in the fourth figure in all the logarithms affected. This is, 

 we think, with the exception of the asterisk, the best method that has been 

 used. The chief defect, or rather point capable of improvement, is that tho 

 three leading figures in the logarithms are not separated, or in any way dis- 

 tinguished, from tho rest of the figures in the block, as is the case in Callet 

 and others. The table was read (wholly or partially) altogether nine times 

 with different tables of logarithms (four of those readings were made after the 

 stereotyping), and is no doubt all but perfectly correct. 



One feature of this table is that every last figure that has been increased is 

 marked with a dot subscript. 



