Scientific Lectures. 143 



a given time, say half an liour, or an lionr ; and we can compare that 

 with the standard. There mav be a variation in the wick ; and 

 furthermore we have not the standard of volume ; and hence 

 oiu' measures of liglit by no means compare with our measures 

 of heat. We place our thermometer in boiling water and melting 

 ice, and obtain our standard points from which to measure ; 

 but we have no such standard with regard to light. Yet there 

 is enough known to guide us to a certain extent as to the 

 volume and intensity of light, as well as its healthfulness. The 

 brightest light man has ever made is the electric light, the brilliancy 

 depending upon the magnitude of the battery we employ and the 

 activity of the oxydizing agents. Xext the magnesium light ; then 

 we have the Hare light, modified by applying in the flame platinum 

 or compressed magnesia. The preparation of oxygen gas at a com- 

 mercial price is the great discovery of this century, and which I hope 

 before many months will be introduced into practical use in this city, 

 for there are competent men who have taken hold of the problem 

 with tlie intention of solving it here as it has been solved abroad, 

 and we shall have a light clieaper and more wholesome. In this con- 

 nection let me say that light should come from above, for God 

 Almighty has so arranged it. Tie has given us eyebrows and eye- 

 lashes. The light should be near the ceiling, that it may be trans- 

 mitted from above, and that the impurities from the gas may be 

 carried out. You know I am not addressing the audience 'I addressed 

 an hour ago. Particles which formed your bodies then have gone 

 democratically into this atmosphere, to be remodeled into other 

 forms and figures ; and particles of food of which you partook 

 to-day are now being transmuted into your living selves. We are 

 like the candle flame, ever changing. We have the semblance of 

 identity; but new particles continually enter into our composition, 

 giving us genial warmth and intellectual light. One of the grandest 

 features connected with humanity is his ability to produce and evolve 

 these imponderable agencies, heat and light. It is a God-like 

 attribute, and one of the most important, not only to tlie health of 

 the body, but the wealth of the pocket. 



I have endeavored in this short time to touch upon the salient 

 points in this extensive field of investigation. I will now ask your 

 patience for a moment, while I allude to a beautiful theory, sustained 

 by some electrical experiments, showing the relation between undu- 

 lations of light and of the atmosphere. If I pass a ray of light 



