171 



SCIENTIFIC MISCELLANEA. 



On the Detection or Dhowned Bodies, by the Kepresentatiok 

 or their Forms on the Ice immediately above them — It may not be 

 generally known that, under certain circumstances favourable to the pheno- 

 menon, the outline tracery of figures reposing at the bottom of a sheet of 

 Water, are occasionally visible on the surface of the ice. I remember per- 

 fectly well, when many years ago hearing this asserted as a fact, it was consi- 

 dered as a pure phantom of the imagination by some, and by others as a mi- 

 raculous interference of providence for the discovery of the body. It is, 

 nevertheless, perfectly true ; imagination has nothing to do with it ; and the 

 miracle resolves itself into a very simple, but curious, operation of natural 

 causes, which, not for the first time, I have verified by repeated observations 

 during the present winter; when my attention was recalled to the case by 

 remarking, after a hard and sudden frost, the exact outline of a semicircular 

 piece of masonry beautifully drawn in white lines in the ice, reminding me 

 of the profile figures incased in solid glass by a patent process of (I believe) 

 Messrs. Pellat and Oreen. To those who are in the habit of looking at 

 things without much minute inquiry, the pictures drawn by an invisible 

 })ower certainly assume a very mysterious appearance , and it can scarcely be 

 matter of surprise that, if the figure of a human being above should prove, as 

 it always must do, indicatorial of a human being below, an ignorant or super- 

 stitious person would naturally attribute such a manifestation as the result 

 of a supernatural draughtsman . The explanation, however, is easy — merely 

 this : we know that any body containing air, if heavier than water, must be 

 emitting that air in minute portions or bubbles, struggling, by their light- 

 ness, to escape through the pores of the submerged body, and rising, if the 

 water is perfectly motionless, in direct straight lines, to the surface. Sup- 

 pose then, that, during the escape of such minute bubbles, a severe and 

 sudden frost takes place ; as a matter of course, on the very first formation 

 of a thin film of ice, the ascending bubbles will be checked and detained by the 

 crystallizing ceiling above them, and remain stationary, and in a few seconds 

 be imprisoned ; such will also be the fate of the successive series : and, con- 

 sequently, if from every part of a subcumbent body, these minute particles 

 are rising, a representation immediately above the body will be the obvious, 

 effect. To those who may not have witnessed this interesting, surprising, 

 but yet simple, phenomenon, the following easy mode of proving it by expe- 

 riment is recommended. Take a piece of porous dry wood, and place it gen- 

 tly in a large shallow tub full of water, pressed down with some weights to 

 keep it steady and prevent its rising, at a time when congelation is rapidly 

 going on, and the air perfectly calm. In the morning, on looking at his tub, 

 the spectator will, if everything has gone on favourably, be gi-atified with 

 seeing the image of his piece of wood faintly or strongly depicted, and incor- 

 porated in minute bubbles through the surface of superincumbent ice, pro- 

 portioned to the quantity or rapid rising of the stream of escaping air. It is 

 scarcely necessary to add that should a human body chance to be in that 

 peculiar state of decomposition, or putrefaction, when gases are generating 

 and evolving, a rapid and abundant ascent of such gases will, on meeting the 

 surface above, be imprisoned in thrilling characters of ribbed ice, to tell the 

 &tal tale «f what has taken place below. E. S. 



