"It was different with subjects more to my mind. Looking over my father's books one day, I came upon Gregory's 'Handbook of Inorganic Chemistry,' and began reading it. I was fascinated with the book, and studied it morning, noon, and night--in fact, every time when I could snatch a few minutes. I really believe that at one time I could have repeated the whole of the book from memory. Now I found the value of arithmetic, and set to work in earnest on proportion, vulgar and decimal fractions, and, in fact, everything in school work that I could turn to account in the science of chemistry. The result of this sudden application was that I was seized with an illness. For some months I had incessant headache; my hair became dried up, then turned grey, and finally came off. Weighing myself shortly after my recovery, at the age of fifteen, I found that I just balanced fifty-six pounds. I took up mensuration, then astronomy, working at them slowly, but giving the bulk of my spare time to chemistry. "In the year 1869, when I was sixteen years old, I came across Cuthbert Bede's book, entitled 'Photographic Pleasures.' It is an amusing book, giving an account of the rise and progress of photography, and at the same time having a good-natured laugh at it. I read the book carefully, and took up photography as an amusement, using some apparatus which belonged to my father, who had at one time dabbled in the art. I was soon able to take fair photographs. I then decided to try photography as a business. I was apprenticed to a photographer, and spent four years with him--one year at Northallerton, and three at Darlington. When my employer removed to Darlington, I joined the School of Art there. "Having read an account of the experiments of M. E. Becquerel, a French savant, on photographing in the colours of nature, my curiosity was awakened. I carefully repeated his experiments, and convinced myself that he was correct. I continued my experiments in heliochromy for a period of about two years, during which time I made many photographs in colours, and discovered a method of developing the coloured image, which enabled me to shorten the exposure to one-fortieth of the previously-required time. During these experiments, I came upon some curious results, which, I think, might puzzle our scientific men to account for. For instance, I proved the existence of black light, or rays of such a nature as to turn the rose-coloured surface of the sensitive-plate black--that is, rays reflected from the black paint of drapery, produced black in the picture, and not the effect of darkness. I was, like Becquerel, unable to fix the coloured image without destroying the colours; though the plates would keep a long while in the dark, and could be examined in a subdued, though not in a strong light. The coloured image was faint, but the colours came out with great truth and delicacy.