The work of Graham, concerned as it mostly was with the development of the conception of atoms, connects the time of Dalton with that in which we are now living. I have therefore judged it advisable to devote a short chapter to a consideration of the life-work of this chemist, before proceeding to the third period of chemical advance, that, namely, which witnessed the development of organic chemistry through the labours of men who were Graham's contemporaries. The printed materials which exist for framing the story of Graham's life are very meagre, but as he appears, from the accounts of his friends, to have devoted himself entirely to scientific researches, we cannot go far wrong in regarding the history of his various discoveries as also the history of his life. * * * * * THOMAS GRAHAM was born in Glasgow, on December 21, 1805. His father, James Graham, a successful manufacturer, was in a position to give his son a good education. After some years spent in the ordinary school training, Graham entered Glasgow University at the early age of fourteen, and graduated as M. A. five years later. It was the intention of Graham's father that his son should enter the Scottish Church; but under the teaching of Dr. Thomas Thomson and others the lad imbibed so strong a love of natural science, that rather than relinquish the pursuit of his favourite study, he determined to be independent of his father and make a living for himself. His father was much annoyed at the determination of his son to pursue science, and vainly attempted to force him into the clerical profession. The quarrel between father and son increased in bitterness, and notwithstanding the intervention of friends the father refused to make his son any allowance for his maintenance; and although many years after a reconcilement was effected, yet at the time when Graham most needed his father's help he was left to struggle alone. Graham went to Edinburgh, where he pursued his studies under Hope and Leslie, professors of chemistry and physics respectively--men whose names were famous wherever natural science was studied. Graham's mother, for whom he had always the greatest respect and warmest love, and his sister Margaret helped him as best they could during this trying time.