From Chapter 1:
Every one knows the legend of the water (or beer) thrown over Sir Walter by his servant when he first saw his master smoking, and imagined he was on fire. The story was first associated with Raleigh by a writer in 1708 in a magazine called the British Apollo. According to this yarn Sir Walter usually "indulged himself in Smoaking secretly, two pipes a Day; at which time, he order'd a Simple Fellow, who waited, to bring him up a Tankard of old Ale and Nutmeg, always laying aside the Pipe, when he heard his servant coming." On this particular occasion, however, the pipe was not laid aside in time, and the "Simple Fellow," imagining his master was on fire, as he saw the smoke issuing from his mouth, promptly put the fire out by sousing him with the contents of the tankard. One difficulty about this story is the alleged secrecy of Raleigh's indulgence in tobacco. There seems to be no imaginable reason why he should not have smoked openly. Later versions turn the ale into water and otherwise vary the story.

From Chapter 6:
The clay pipes called "aldermen," with longer stems than their predecessors, tipped with glaze, came into use towards the end of the seventeenth century. They must not be confused with the much longer "churchwarden" or "yard of clay" which was not in vogue till the early years of the nineteenth century.