288 Mr. Ritchie'^ Experiments 



fully distressing to some persons. One grain of calomel has 

 been known to produce a salivation of weeks, and to produce an 

 instantaneous eruption. Opium frequently produces violent 

 irritation of the skin, and many judicious physicians never pre- 

 scribe it to strangers, without inquiring whether they have ever 

 taken it before, and with what effect. Fallopius mentions an 

 abbess of Pisa, to whom he often prescribed pills, who never 

 swallowed them, but crushed them flat with her fingers, which 

 speedily produced an effect. 



The odour from ipecacuanha has produced very violent effects. 

 A lady's maid putting her lady's cap into a wardrobe, became 

 instantly affected with nausea. No notice was taken of it, it 

 was considered as accidental. A few days afterwards, going to 

 the same wardrobe for the cap, she was again seized with nau- 

 sea and sickness. She then said she was sure there must be 

 ipecacuanha there, and so it turned out, — for my lady's hus- 

 band had bought a box of ipecacuanha lozenges, and had un- 

 consciously left them in the wardrobe. 



Experiments on Heated Iron, in reference to the Magnetic 

 and Electric Fluids. — By William Ritchie, A.M., Rector 

 of the Royal Academy at Tain. 



(Communicated by the Author.) 



In repeating some of the interesting experiments of Professor 

 Barlow on the magnetism of heated iron, I was led to some 

 curious results, which, as far as I remember, have not been 

 previously observed. The magnetic needle I employed, con- 

 sisted of a piece of steel wire suspended by a single fibre of 

 silk, and thus preserved extreme delicacy. I bent a piece of 

 stout iron wire into the shape ACB, 

 having the portions at AB exactly equal, 



so that the point of the needle S, could ^^ ^TIT*" N 



be acted on with the same forces when 

 the wire was cold. 



Experiment 1. Raise two or three inches of B to a white 

 heat, bring AB equally distant from S, and the needle will be 

 drawn towards A. When B has sunk to a red heat, the needle 



d c{ s— 



