MECHANICS AND USEFUL ARTS. 71 



assimilation of weights, measures, and coins in different countries. 

 The North German Confederation of 1868 adopted the metre as 

 the basis of measures and weights, and resolved to take as the 

 primary standard measure of length the platinum bar in posses- 

 sion of the Prussian government. This bar is equal to l.OUO-OoOl 

 metre at the temperature of melting ice. Metre weights and 

 measures are made legal in the United States, and are employed 

 in post-office exchanges with foreign countries. It were much 

 to be desired that our post office would follow the good example. 

 Still greater progress had been made in the introduction of the 

 metrical system into India, — v/ith regard to which the report 

 entered into particulars. Efforts had been made to promote the 

 adoption of the same system in the colonies. The second report 

 of the royal commission had lately recommended the removal 

 of every difficulty, and the full and legal introduction of the metric 

 system. Chambers of Agriculture and Commerce (including the 

 Barnstable Farmers^ Club) had petitioned Parliament in favor of 

 a uniform system of weights and measures. With resj^ect to in- 

 ternational coinage no further step had been taken since the 

 report of the royal commission. The Chancellor of the Ex- 

 chequer had, however, recently enunciated his views in favor of 

 imposing a seignorage of aboul one per cent, for coining gold into 

 sovereigns. This was a difficult question, and the committee 

 contented themselvos with echoing the recommendation of the 

 Toycil commission, that another international congress be speed- 

 ily held to consider the scheme. In conclusion, the report rec- 

 ommended the reappointment of the committee for the purpose 

 of further stimultiting the early realization of a uniform s^^stem 

 of weights, measures, and coins in all countries. 



NEW OXYGEN PROCESS. 



Oxygen procured cheaply and easily, is, as we have often said, 

 a very desirable thing. Tlie numerous applications that could be 

 made of it are so evident that we need not stop to mention them, 

 but we lay before our readers yet another plan, and this time an 

 ingenious one, for obtaining it. The mineral sources of oxygen 

 being comparatively expensive, MM. JMontmagnon and Delaire 

 have betaken themselves to that cheap reservoir, our atmos- 

 phere, and have further availed themselves of the discriminative 

 action of wood charcoal and water, or certain saline solutions. 

 We give here, it must be understood, the figures of the authors 

 named, without checking them by a reference to the figures of 

 Dr. Angus Smith, wiio has made most careful experiments on the 

 absorptive action of charcoal. According, then, to our authors, 

 100 litres of fresh wood-charcoal will, when exposed to atmos- 

 pheric air, occlude 925 litres of oxygen, but only 705 litres of 

 nitrogen. Now, it would appear that when the charcoal so sat- 

 urated with gas is thoroughly saturated with water, there will be 

 expelled 650 litres of nitrogen, but only 350 litres of oxygen. 

 Thus we have now left in the pores of the charcoal 575 litres of 



