80 Mr. Spitspury on a Single Galvanic Combination. 
and above it, it will become positive; the former positive wire 
being negative. 
The next enquiry was whether the same phenomena were 
observable in other alloys. The first tried was pewter, which was 
regulated by similar laws; but the intensity of magnetism produced 
was considerably less, than when brass was employed. An alloy 
of silver and copper, called by the platers coarse silver, (a little 
finer than standard), had a much greater effect; standard silver 
had about the same power as the last; but in an alloy of zinc, 
copper, and silver, the intensity was very much increased. It is 
however worthy of remark, that no alloy, not even brass, was 
capable of exciting so intense an effect as iron. May not this be 
taken as a further argument in favor of carbon being the oxide 
of a metal, which has an affinity for oxygen surpassing all other 
metals, as Dr. Mac Culloch has attempted to prove in a late very 
able paper printed in the Edinburgh Journal? 
All these alloys are regulated by the law of the larger surface 
being positive to the less. The followimg may be taken as the order 
of the intensity, in which magnetism is produced by each of those 
tried. 
Iron wire (called binding.) 
Brass. 
Silver solder, (brass, copper and zinc.) 
Coarse silver, (copper and silver.) 
Standard silver. 
Pewter, (tin, lead and antimony.) 
Tin of commerce. 
Copper of commerce. 
From the foregoing list it will appear, that some effect was 
produced by the simple metals themselves, as met with in com- 
merce. To ascertain, if this arose from accidental impurities com- 
bined with them, er from a property hitherto undiscovered, two 
