36 



inch, then the lamp appeared safe, under all circumstances, in mix- 

 tures of coal gas and air. 



With a view to explain the non-transmission of inflammation 

 through small apertures, the author considers the nature of flame in 

 general ; and since a piece of phosphorus, or even a small taper, will 

 burn in the midst of a large flame made by the combustion of al- 

 cohol, he is of opinion that oxygen exists in the centre of all flame, 

 forming an explosive mixture with the vapour, but which burns 

 solely at the exterior surface, because it is there alone sufficiently 

 heated to take fire. 



If a piece of wire-gauze be held in the flame of a lamp, or of coal 

 gas, no flame passes through the gauze ; for though a portion of the 

 inflammable vapour passes, it loses too much heat in its passage to 

 propagate the flame ; but in the case of inflammable mixtures of coal 

 gas entering a lamp, and burning at the interior surface, that which is 

 exterior has not been exposed to any heating cause, and consequently 

 is in no danger of taking fire at the sides of the lamp ; and the results 

 of combustion which escape at the top, though heated, are no longer 

 inflammable. 



In conclusion the author informs us, that these lamps have now 

 been tried in two of the most dangerous mines near Newcastle with 

 perfect success ; and he has great hopes that they will shortly be 

 adopted in many of the collieries in that neighbourhood. 



Some Observations and Experiments made on the Torpedo of the Cape 

 of Good Hope in the Year 1812. By John T. Todd, late Surgeon 

 of His Majesty's ship Lion. Communicated by Sir Everard Home, 

 Bart. V.P.R.S. Read February 15, 1816. [Phil. Trans. 1816, 

 p. 120.] 



The fish on which these experiments were made, were generally 

 caught early in the morning, and examined as soon after as possible, 

 but in some instances were kept in buckets of water as long as three 

 days, or more. 



They are frequently caught by the seine in Table Bay, to the west- 

 ward of the Cape, but very rarely in Simon's Bay, which is to the 

 eastward, and never caught by the hook with any kind of bait. 



The Torpedo of the Cape differs in no respect from those of the 

 Northern Hemisphere, except in size, which is never more than eight 

 inches long and five in breadth. The columns of their electric or- 

 gans appeared larger and less numerous than those described by 

 Mr. Hunter. The form of any one singly is cylindric, but in a sec- 

 tion of a whole organ the figure is modified by lateral compression. 



The author found the supply of nerves to these organs, agreeably 

 to former descriptions, to be larger than to any other parts. 



The greatest shock they give was never felt above the shoulder, 

 and rarely above the elbow joint, the strength of it depending more 

 upon the vivacity of the animal than upon its size. There appeared 



