180 Rev. Mr Scoresby on the Uniform PermeaUlity of 



By the use of two elements, — number of blows and an extra 

 interval of time in different parts of the series, — an abundant 

 code of signals might be arranged within the limits of not more 

 than eight or nine blows in succession*. 



• The following may serve as an illustration of the method proposed for 

 signalizing by means of blows. The number might be increased, and the 

 signals modified, by employing scratchings with the point of a pick-axe, which 

 can be heard at considerable distances, as well as by the method of blows. 



Directions by the Experimenter 

 observing the Deviations. 



2. Attention. 



3. Apply the magnet (N. pole) 



where you are ; as near as 

 you can tell opposite me, at 

 the floor of the mine. 



4. Reverse the pole of the magnet, 



and apply it to the same 

 spot. 



5. Neutralize the magnets. 



1, 2. Apply the N. pole of the mag- 

 net to the middle of the 

 working, at the floor of the 

 mine. 



1, 3. Carry the magnet to the right 

 on the same level. N.B. The 

 distance in yards to be indi- 

 cated by the number of suc- 

 cessive blows. 



1, 4. Ditto to the extreme right of 



the mine ; same level. 



2, 1. Ditto to the left, so many 



yards. 



2, 2. Ditto to the extreme left of 



the mine. 



2.3. Raise the magnet vertically 



from the floor, so many feet. 



2.4. Raise it to the roof, directly 



upward. 

 3, 1. Depress it to the floor, directly 

 downward. 



3, 2. The experiment is finished. 



3, 3. The experiment is not finished. 

 3, 4. Do you understand ? 



Answers or Inquiries by the Ma- 

 nager of the Magnets. 



Indication. 



2. We are attending. 



No. of 



blows. 



3. It is done. 



4. It is reversed. 



5. They are neutralized. 

 1, 2. It is so applied. 



1, 3. It is so applied. 



1, 4. It is at the extreme right. 

 2, 1. It is so applied. 



2, 2. It is at the extreme left. 

 2, 3. It is raised as directed. 



2, 4. It is at the roof. 

 3, 1. It is at the floor. 



3, 2. Is the experiment finished ? 



3. 3. I understand. 



3.4. I do not understand. What 

 do you mean ? 



