AID RENDERED BY PHOTOGRAPHY TO GEOLOGY. 
31 
Fortunately the sun shone right down the cave, and it was an 
easy matter to secure an excellent photograph of the bones 
before they were disturbed. 
Very many cases have occurred of the uncovering of 
skeletons and other objects in burial grounds, and even of the 
illustrious dead in our cathedrals, &c., where all trace of the 
objects faded away in a few minutes after exposure to the air ; 
the bones crumbling to dust with a touch. If the forethought 
had been taken to have a camera at hand, many other pictures 
might have been secured of great value to the scientist and 
the historian. 
Lastly, I am sure no one will acknowledge more freely the 
aid which photography can render to geology than that excel¬ 
lent geologist, Dr. Jolmstone-Lavis, F.Gr.S., who is employing 
the camera freely as an aid to his studies of the volcanic 
phenomena of Vesuvius; studies which have now extended 
over some considerable time, and which are encouraged and 
aided by the British Association. 
All volcanic regions are subject to rapid changes of form 
and level, and a record of such change is of the highest 
importance in the study of vulcanology. The cone of 
Vesuvius, we know, has undergone most wonderful changes in 
the past. The hill we call Monte Somma, and the lower 
elevation of La Pedimentina, are relics of an old cone of far 
greater dimensions than tlie existing one ; and a series of 
photographs, showing the condition of the volcano at regular 
and frequent intervals since that mighty eruption in a. d. 79, 
which overwhelmed Pompeii, would indeed be interesting and 
important. But if it is not possible to now recall the past, 
we can at least provide for the future, and this is just what 
Dr. Lavis is doing, by securing almost daily photographs of 
the crater, plain, and the interior and exterior of the cone of 
eruption. These change rapidly, sometimes within an hour 
or two, and the changes afford an important clue to the nature 
and action of the important, but as yet somewhat mysterious, 
forces which are at work beneath Southern Italv. Some of 
«/ 
Dr. Lavis’s photographs were exhibited during the meeting of 
the British Association at Birmingham in 1886, and will be 
reproduced in a journal which is published by the Naples 
section of the Italian Alpine Club. 
In writing these few lines I have merely jotted down the 
first three instances which occurred to me of the aid which 
photography has been able to render to one science only, viz., 
geology. Did time and space permit, books might be written 
describing the assistance which this young art— not yet half a 
century old—has rendered in all branches of science and art. 
