Fossil Encrinite. 359 



the southei*!! magnetism repulsed. In taking this movement of 

 the northern and southern magnetism for the commencement of 

 revokuions in opposite directions of the two figures, they can be 

 put in the hehx in a corresponding manner, the situation of the 

 figures which result from it will account then for the direction of 

 the electric current. 



If a southern pole, for example, is turned to the left around 

 its axis, let us fancy the symbol of the southern magnetism in- 

 troduced into the interior of the magnet in a situation corres- 

 ponding to the direction of rotation : the electric current resulting 

 from this, will be directed then from the head of the figure 

 spoken of towards the feet. It is evident that the wire com- 

 municating to the southern pole, receives the northern magnet- 

 ism at the place of contact, whether this contact is effected imme- 

 diately or by the agency of the mercury. It will be seen that 

 this wire will turn respectively to the right if the southern pole 

 turns to the left, conformably to our symbol. And in effect, is 

 the essejitial point in this trial, and departing hence, we can 

 easily obtain a long series of varied and instructive experiments. 



It is necessary to warn all those who intend to repeat them, 

 to take all precautions to avoid thermo-electric currents, the mul- 

 tiplier described above being very subject to them. In effect, 

 it can be easily demonstrated in experimenting in the man- 

 ner indicated above, that the thermo-electric current is greater 

 than an hydro-electric current produced by a single pair of zinc 

 and copper disks, which are about equal in size to a crov/n, (or 

 half dollar,) and are wetted with a solution of muriate of soda. 



Art. XVIIT. — Fossil Encrinite ; by John G. Anthony. 



Cincinnati, September 11th, 1838. 



TO PROF. SILLIMAN. 



Dear Sir — Enclosed I send you a drawing of a speci- 

 men in my collection, which I found near this place in March 

 last. The first specimen of this fossil was discovered by myself 

 a year since, and consisted merely of the reticulated part, with- 

 out any stem, and but a small portion of the fimbrice. During 

 the past winter more than seventy similar specimens were washed 

 out by the rains from the rubbish of a quarry, and picked up, — 



