Miscellanies. 199 



12. Porcelain Clay. — We have a specimen of clay from Granby, 

 Conn, which very much resembles the porcelain clay of Limoges 

 in France. Under the compound or oxy-hydrogen blowpipe, it 

 vitrifies into a white enamel, and exhibits no tinge of color. We 

 are informed that it exists in a thick bed a few feet below the sur- 

 face, and that measures are about being taken to explore it, and to 

 ascertain its properties more effectually. — Ed. 



13. Galvanic currents. — In the decomposition of water by the gal- 

 vanic power, two tubesbeing filled with water, (see the figure on the next 

 page,) and inverted in a vessel filled with that fluid, their orifices being 

 about one inch apart, and the connexion established through the fluid, 

 by slips of platina, I had recently the satisfaction of observing, dis- 

 tinctly, the currents of gas as they took their departure to their re- 

 spective poles. It has been a problem, whether the water is decompo- 

 sed under one tube, or the other tube, or at some intermediate point ; 

 but, in the experiment referred to, ocular demonstration was exhibited, 

 that the decomposition took place, simultaneously, under both tubes, 

 and not at any intermediate point. This appeared from the fact, that un- 

 der each tube, a current of gas rose, vertically, from the platina slip, and 

 collected in the top of the tube, while another current shot off, laterally, 

 and took up its march, towards the opposite pole beneath the contig- 

 uous tube ; as this process was going on at the same time, under both 

 tubes, it follows that there were opposite currents of gas, but they 

 occasioned less mutual disturbance dian might have been supposed ; 

 because the levity of the hydrogen and the gravity of the oxygen 

 determined them to pass each other at different levels, and although 

 many bubbles were buoyed up in the passage and made their escape, 

 and were lost, by passing through the water intermediate between the 

 two tubes, a large part of the gases was collected in the respective 

 tubes. The process was continued for several hours with a large 

 battery,* and the currents were palpable to all the bystanders. 

 With a magnifying glass the appearance was beautiful, and nothing 

 can exhibit more decisively the all dominant power of the galvanic 

 influence in causing even gaseous elements to separate at different 

 points, and to pass horizontally, in opposition, through at least two 

 inches of water, until they arrived at the poles by which they were 

 respectively attracted. But on examining the gases in the two tubes, 

 so far from finding the oxygen gas in the one and hydrogen in the 



* 720 pairs of G and 4 inch plates. 



