304 Notices respecting New Booh. 



two figures, and to express ^ three figures are necessary ; — 

 and are ratios of such frequent occurrence of no importance ? 

 They would no doubt occur less frequently were money, time, 

 weights, and measures all decimally divided ; but what does 

 this concession involve? Nothing less than an entire change 

 of language in all cases where any thing relating to time, 

 weight, prices, or measures is the subject ; and with a less de- 

 gree of change the inconvenience of a decimal division will be 

 much greater than the ones now in use. 



The advocates for decimal division do not appear, as far as 

 I have seen, to have studied the nature and advantages of the 

 old divisions. For example, in the division of time all the 

 prime digits are factors, the principal divisions are by 60th 

 parts, and 60 is composed of 2 2 X 3 X5; the only prime digit 

 not included, being 7; and we only want a more convenient 

 notation to render it far superior to any decimal division ; su- 

 perior both in the facility of expressing minute parts, and in 

 expressing large numbers. The number 10 is too small for 

 such an object ; the cube of 10 is not equivalent to the square 

 of 60, besides the defect of not enabling us to express ^, jr, ^, 

 &c. I have had several schemes for improving the notation ; 

 and though I have not hit upon one of sufficient convenience, 

 the success has been such as to render it pretty certain that 

 the thing is not impossible. 



I am, gentlemen, 



Your most obedient servant, 



Thomas Tredgold. 



LII. Notices respecting Nexo Books. 



Recently published. 



PRACTICAL System of Algebra, designed for the Use 

 of Schools and private Students. By P. Nicholson, and 

 J. Rowbotham. 



A 



Preparing for Publication. 



An Explanatory Dictionary of the Apparatus and Instru- 

 ments employed in the various Operations of Philosophical 

 and Experimental Chemistry. In 8vo., with seventeen Quarto 

 Copper-plates. By a Practical Chemist. 



The Farmer's, Shepherd's, and Mariner's Pocket Dictionary, 

 containing rules for judging of the weather, &c. alphabetically 

 arranged. 



LI 1 1. Pro- 



