In 1826 John Clerk Maxwell married Miss Frances Cay, of North Charlton, Northumberland. For the first few years of their married life their home was in Edinburgh. The old estate of Middlebie had been greatly reduced in extent, and there was not a house on it in which the laird could live. However, soon after his marriage, John Clerk Maxwell purchased the adjoining property of Glenlair and built a mansion-house for himself and his wife. Mr. Maxwell superintended the building work. The actual working plans for some further additions made in 1843 were his handiwork. A garden was laid out and planted, and a dreary stony waste was converted into a pleasant home. For some years after he settled at Glenlair the house in Edinburgh was retained by Mr. Maxwell, and here, on June 13, 1831, was born his only son, James Clerk Maxwell. A daughter, born earlier, died in infancy. Glenlair, however, was his parents’ home, and nearly all the reminiscences we have of his childhood are connected with it. The laird devoted himself to his estates and to the education of his son, taking, however, from time to time his full share in such county business as fell to him. Glenlair in 1830 was very much in the wilds; the journey from Edinburgh occupied two days. “Carriages in the modern sense were hardly known to the Vale of Urr. A sort of double gig with a hood was the best apology for a travelling coach, and the most active mode of locomotion was in a kind of rough dog-cart known in the family speech as a hurly.”[2] Mrs. Maxwell writes thus[3], when the boy was nearly three years old, to her sister, Miss Jane Cay:-- “He is a very happy man, and has improved much since the weather got moderate. He has great work with doors, locks, keys, etc., and ‘Show me how it doos’ is never out of his mouth. He also investigates the hidden course of streams and bell-wires--the way the water gets from the pond through the wall and a pend or small bridge and down a drain into Water Orr, then past the smiddy and down to the sea, where Maggy’s ships sail. As to the bells, they will not rust; he stands sentry in the kitchen and Mag runs through the house ringing them all by turns, or he rings and sends Bessy to see and shout to let him know; and he drags papa all over to show him the holes where the wires go through.” To discover “how it doos” was thus early his aim. His cousin, Mrs. Blackburn, tells us that throughout his childhood his constant question was, “What’s the go of that? What does it do?” And if the answer were too vague or inconclusive, he would add, “But what’s the _particular_ go of that?”