Classic coil

Hello everyone !

I have been rereading my reprint of Teslas lecture to the Institution of Electrical 
Engineers in London. On page 15, he describes a small bipolar coil. Each of the  
terminals of the coil is connected to a circle, one is 80 cm in diameter, the other is 
30 cm in diameter. During operation of the coil, the discharges between the 
terminals produce a "luminous sheet" with an area of about 0.43 square metre. He 
states that he in earlier experiments, using bigger circles had covered an area of 
more than one square metre. 
This coil has 2 primaries with 96 turns in each, and two secondaries with 260 turns in 
each. When both the primaries and the secondaries are connected in series, this 
gives a ratio of conversion of about 1:2.7.

It seems that a lot of people are designing coils with much bigger conversion ratios 
(1:67 for a coil with 1000 windings on the secondary and 15 on the primary). I would 
say that Teslas results with this coil are quite impressive. Why the big secondaries 
in "modern" coils ? 

Hans J|rgen Grimstad