of Edinburgh, Session 1881 - 82 . 
733 
the cell is nearly exhausted, it then falls off rapidly. In the 
secondary cell it usually falls off from the beginning, or at any rate 
very soon after the cell begins to run down. This is due to increase 
of internal resistance from the using up of the cuprous chloride and 
the zinc. These cells usually run themselves out completely, 
leaving no zinc deposit. 
To recapitulate the peculiarities of this cell. It is a one-fluid 
cell, and therefore does not suffer from diffusion. 
Its internal resistance is very low. 1 *2 ohm for 1 square inch 
surface. Its EME is *75 volt. 
It does not suffer from polarisation, nor does it give off any gas 
either during charging or running down. 
When being charged it increases in internal resistance. 
The experiments on the next page are selected from many, as 
being fairly favourable specimens of the action of the cell. 
I have not said anything here on my views of the practical 
application of secondary cells to electric lighting, or of how I 
propose to use my cell. I hope to be able to lay a future paper 
before the Society on this subject. I should mention that this cell 
has been patented in my name as a secondary battery by Mr. Swan 
of Newcastle. 
Primary tray cell , 6 sq. in. surface,* weight = ~ lb. 
Current varying from 3 ‘5 to 5 # 5 Amperes. 
1st minute, 4 ’2 Amperes. 
45th minute, 4 Amperes, then rapidly falling. 
Average for 45 min., 4 Amperes. 
Work expended in circuit = 5950 ft. lbs. 
Average internal resistance, 0*2 Ohm. 
16 tray cells occupying 4" x 5" x 4", and weighing about 
3 lbs., supported a small Swan lamp for 1 hour 10 
minutes at 1 candle. 
Secondary Tray Cells. 
1st cell. Surface 7 sq. in., f" between trays. 
EMF of cell before use, 0’8 Volt. 
After 12 minutes, current = 3T Amperes. 
EMF = 0-7 Volt. 
* By the “ surface ” is meant the surface of one plate, not of both together. 
