say tbafc the past and present enormous consumption of coal 
eventually produces man. and accounts for the increase of car- 
bon in the human race. These changes are mainly occasioned 
by the sun's agency, for without sunlight, solar hear, and 
solar chemical power no plant could grow and no carbonic 
acid could be decomposed. Solar light is thus the source of 
all man's power and thought and motion, but we must not 
look upon it as the first primary cause, for the Great Archi- 
tect of the universe promulgated the laws which have 
governed the action of light, heat, and chemical agency 
of the solar power ever since the creation of the world. 
The Rev. W. Whiting, M.A., then made a verbal com- 
munication on the subject of transparent slides for magic 
lanterns for educational purposes. He bad given this sub- 
ject much attention, his endeavour having been to popularise 
science by exhibiting in the magic lantern transparent pho- 
tographs of microscopic objects. The Government had 
shown their appreciation of the benefits derived from the 
exhibition of good subjects in the raagic lanterns by order- 
ing a complete set of the apparatus and slides to be sent to 
I the depots of all regiments. Various papers have been 
published at different times on micro-photogranhy, making 
difiiculties and discouraging persons from taking the sub- 
ject in hand. Mr. Whiting said he had found no 
I difficulty, whereas many had put the expense of necessary 
I apparatus at from £25 to £40. His apparatus cost less than 
I £4, and produced results he had brought with him to show. 
He exhibited a large French camera which, he said, was not 
worth 2s. 6d., and a Field's microscope, sold complete for 
1 £3 lOs. This was the whole of the apparatus he used. He 
found Field's microscope better than many more expeFsive 
ones by the best makers, as the chemical and visual foci of 
the lenses were coincident. Mr. Whiting mentioned several 
ingenious contrivances which are likely to be serviceable to 
photographers. Instead of a ground glass for focussing, he 
used glass on which a film of collodion containing four grains 
of rosin per ounce had been spread. Mr. Whiting exhibited 
a choice selection of photographs of microscopic objects, and 
promised on a future occasion to go further into the subject 
of micro-photography. Before concluding he said that he 
quite considered that photography should be in subserviency 
to chemistry, and that it was one of the objects of the section 
that photographers should state their difficulties for chemists 
to remove them. In that hope he mentioned a paper pub- 
' lished by M. Poitevin, stating that the vapour of benzine 
I appeared to sensitise in some measure plates covered with 
insensitive iodide of silver. He simply brought this subject 
forward, hoping some one might take it up. and remarked 
what a boon it would be if photographers could sensitise dry 
plates by simply exposing them to a vapour. 
T. H. YABBICOM. 
F. ASHMEAD, 
A. NOBLE, 
WM. LANT CARPENTER, 
Honorary Reporting Secretary, 
