ARTIFICIAL ILLUMINATION, 173 
DISCUSSION. 
Tue CuarrmMan.—lI do not think that any of us would have guessed that Pro- 
fessor Lambert was under any disadvantage after the delightful and brilliant lecture 
which he has given us. He has said that he will be very willing to answer any 
questions that any gentleman may wish to ask about his lecture or about any kind 
of lighting in which you may be interested. 
Proressor LamBert.—Within my ability I shall be glad to answer any ques- 
tion, and I shall welcome any enquiry which may bear upon any point that [ have 
not made clear in my lecture. 
CoLONEL Watkin, C.B.—I am sure we have all been most interested in the 
lecture that we have just heard, it has been most enjoyable and interesting, and at 
the same time most economical, as I for one shall now inspect my gas burners. 
I think we have all had the same sort of idea that a small gas burner was an 
economical one, because the cook could not turn on the gas too high; but now 
we find that she would be quite right in having a large burner. 
I think, Sir, the subject is one of the most interesting to those of us who, like 
myself, are getting on in years and who are obliged to work under artificial light 
at night. Iam sorry to find that our old friend electricity, which has done and is 
doing so much for us, is being ousted in that one particular sphere in which we 
thought it was paramount, namely illumination ; but certainly my own experience 
of incandescent gas light coincides with that of the Lecturer in finding what a 
beautiful light itis. I think very few of us, without trying it for ourselves, 
would know really what an advantage it has over other lights. Statistics such as 
those given by the Lecturer, are very interesting, but do not appeal to one, in the 
same way as a practical trial. Anybody I feel sure, after once trying these incan- 
descent burners, would use them in preference to the older form. 
But, Sir, there is one point which is very important, and which the Lecturer has 
not told us anything about, and on which I should like to have his opinion, and 
that is the effect upon our eyes of the electric-—incandescent light. I am told 
(and I can quite believe it from my own experience) that the income of the oculists 
has vastly increased since the introduction of the electric light. Why is this ? 
My own theory is that the small filament which we get in the incandescent electric 
burner is so small, as compared with an ordinary gas burner, that the image formed 
on our retina is very small and therefore the sensitive nerves are greatly dis- 
tressed, not to say ruined, by the immense amount of light concentrated on so 
small a space. Whether this is so or not perhaps the Lecturer will be able to tell 
us. We cannot change our eyes like mantles, and they are too precious to be 
trifled with. 
One other point as regards economy I should like the Lecturer to give us some 
imformation about. I saw the other day an advertisement in the Times of a rival 
company who say that their burners give out more light per cubic foot of gas; 
that the mantles are not so delicate (and certainly the mantles are rather delicate 
to handle), that they will last longer, and, what is more important, that they are 
less than half the price. Now, if that is so, the future of gas lighting is, I think, 
assured, and our poor old friend, the electric light, will have to take a back seat. 
* 
REPLY. 
Proressor Lampert.—In reply to your question, Sir, about the effect upon 
our eyes I should regard your own explanation as a perfectly correct one. The 
effect on the retina, I take it, is not due only to the quantity of light which is re- 
ceived in the eye but to the intrinsic {Illumination of the image at the back of the 
eye. It hurts nobody’s eyes to be out in the open in the diffused light of an 
ordinary fine day, and yet the quantity of light which enters the eyes then is 
