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Art. ^ 111 . ^Account of Electro-Magnetic Experime^its made 
by MM. Van Seek, Professor Van Rees qf Liege, and Pro- 
fesor Moll qf Utrecht In a Letter to Dr Brewster. 
Dear Sir, 
The following electro-magnetic experiments may perhaps not 
be unacceptable to you. They were made jointly with my 
friend Mr Van Beek of this city, and Professor Van Bees of the 
University of Liege. Whatever may be good in them, must be 
almost entirely attributed to the ingenuity of Mr Van Beek, who 
had the principal share in devising and fitting up the apparatus. 
The electrical machine employed consisted of two plates of 70 
centimetres in diameter. The battery was composed of seven Ley- 
den phials, the coating of which contained 5962 square centime- 
tres. We employed steel needles of 7^ centimetres in length, 
as free from magnetism as they could be obtained. We had a 
sensible magnetic needle of five centimetres long, to explore the 
magnetism communicated by electricity to the other needles. 
1. Round a glass-tube was twisted a brass- wire, so as to form 
spiral windings, turning to the right-hand side. A steel-needle 
was put in the glass-tube. The battery was discharged through 
the spiral wire, and the needle was found magnetic, having its 
north pole turned against the negative part of the spiral wire. 
S. The same experiment being repeated, with this difference, 
that the spiral was twisted round the glass-tube to the left hand, 
the needle became magnetic, but its north pole turned towards 
the positive side of the spiral wire. 
It must be observed, that we call the north pole qf the needle, 
that which directs itself to the north, when the needle is freely 
suspended. 
S. A steel-wire, 64 centimetres in length, was put in a glass- 
tube. Round this tube was twisted a spiral brass-wire, the turns 
alternately from right to left, then from left to right, again to 
the left, and so on, alternating eight times on the length of the 
tube. The wire and tube were externally covered with sealing- 
wax, to prevent the electric spark crossing from one winding of 
the spiral to the next, the electric discharge being sent through 
the spiral, and the steel being taken out, had as many different 
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