496 Intelligence and Miscellaneous Articles, 



The sulphate-of- copper solution is by far the most remarkable 

 that we have tried. The smallest globule, on leaving the spheroidal 

 state, gave intense effects, sending the lamp-image entirely off the 

 scale. 



We have also commenced a set of experiments with a view to test 

 the electricity developed during the brisk disengagement of a gas by 

 chemical action, which was discovered eighty years ago byVolta. In 

 some of these experiments it was observed that when the gases were 

 disengaged with considerable effervescence, and in a mass of large 

 bubbles foaming over the platinum crucible in which the experiment 

 was conducted, the bursting of each bubble was attended by a simul- 

 taneous increase of deflection in the electrometer. These experiments 

 are as yet exceedingly imperfect, but they seem, like the preceding, 

 to indicate friction as a main cause of the observed results. The 

 effects on the electrometer are by no means so uniform, either as to 

 kind or quantity of electricity, as those given by evaporation. 



Electricity developed during Effervescence. 



Zn-f-HCl - 750 



Zn+NO s HO +175. In another trial -120. 



MnO°~ + HCl -150 



CaO, CO-f HC1 Trifling effects. 



NaO, S0 2 + HC1 At first a small negative deflection, 



finally + 50. 



NaCl+S03HO + io ' 



— From the Proceedings of the Royal Society of Edinburgh, February 

 1862. 



POSTSCRIPT TO PAPER " ON CHINESE ASTRONOMICAL 

 EPOCHS." 



To the Editors of the Philosophical Magazine and Journal. 

 Gentlemen, 



In my paper "On Chinese Astronomical Epochs " which you pub- 

 lished in your Number for January last, I substituted in a formula the 

 English measure of 12 inches for the foot, whereas I ought to have 

 used 10 only, the French measure. In consequence of this, the 0*25 

 at the top of p. 3 ought to be changed into 0*30. The effect of this 

 is that the range of time within which the Chinese observations may 

 have been made is 45 centuries, instead of 37-^; and therefore the 

 uncertainty arising from the ill-defined termination of the shadow of 

 the gnomon is still greater than I make it in that paper. I shall be 

 much obliged by your inserting this letter in your next Number after 

 receiving it. 



I take this opportunity of asking you to make two more correc- 

 tions; viz. 



Page 3, last line but one, for Nos. 4 and 5 read Nos. 5 and 6. 

 — 6, line 12 from the bottom, for Nos. 2 and 4 read No. 4. 



I am, Gentlemen, 



Yours faithfully, 

 Calcutta, April 1, 1862. J. H. Pbatt. 



Oct 9. 1162 



