VI NOTES BY THE EOITOK 



great convenience, both in science and commerce. I can speak from 

 personal experience of the superiority of decimal measurement in all 

 cases where accuracy is required in mechanical construction. In the 

 Elswick Works [where the Armstrong guns are made. ED.], as well 

 as in some other large establishments of the same description, the inch 

 is adopted as the unit, and all fractional parts are expressed in deci- 

 mals. No difficulty has been experienced in habituating the workmen 

 to the use of this method, and it has greatly contributed to precision of 

 workmanship. The inch, however, is too small a unit, and it would be 

 advantageous to substitute the metre if general concurrence could be 

 obtained. As to our thermometric scale, it was originally founded in 

 error ; it is also most inconvenient in division, and ought at once to be 

 abandoned in favor of the centigrade scale. The recognition of the 

 metric system and of the centigrade scale by the numerous men of 

 science composing the British Association, would be a most important 

 step toward effecting that universal adoption of the French standards 

 in this country which, sooner or later, will inevitably take place ; and 

 the Association in its collective capacity might take the lead in this 

 good work, by excluding in future all other standards from their pub- 

 lished Proceedings." 



In this connection it may be interesting to add that a commission of 

 scientists has recently been convened in Germany, to consider what 

 measures may be best adopted there, to secure uniformity of weights 

 and measures, and the various continental Governments have been 

 called upon to examine the practicability of those which have been rec- 

 ommended. The Bavarian Government states its readiness to adopt 

 the decimal system for weight and long measure, but in surface and 

 cubic measure can only promise to have tables of reduction prepared 

 and circulated. The land-tax, as it exists in Bavaria, is the chief ob- 

 stacle to any simplification of the surface scale, while the fact that there 

 are different measures for fire-wood, for timber, for earth and for stone 

 would cause great confusion if any reform of cubic measure were to be 

 introduced. 



Accuracy of Modern Astronomical Investigations. In another part 

 of the present volume, attention is called to the discrepancy which ex- 

 ists in the estimates of astronomers respecting the solar parallax. This 

 has usually been represented by eight seconds and a half; but accord- 

 ing to the recent calculations of Hansen, the German astronomer, four- 

 tenths of a second should be added, which reduces the distance of the 

 earth from the sun about four millions of miles. At a recent meeting 

 of the Royal Astronomical Society (G. B.), Mr. Pritchard thus rep- 



