During the course of her career Miss Slessor wrote numberless letters, many of them productions of six, ten, twelve, and fourteen pages, closely penned in spidery writing, which she called her "hieroglyphic style." She had the gift, which more women than men possess, of expressing her ideas on paper in as affluent and graceful a way as in conversation. Her letters indeed were long monologues, the spontaneous outpouring of an active and clever mind. She sat down and talked vivaciously of everything about her, not of public affairs, because she knew people at home would not understand about these, but of her children, the natives, her journeys, her ailments, the services, the palavers, all as simply and naturally and as fully as if she were addressing an interested listener. But it was essential that her correspondent should be in sympathy with her. She could never write a formal letter; she could not even compose a business letter in the ordinary way. Neither could she write to order, nor give an official report of her work. The prospect of appearing in print paralysed her. It was always the heart and not the mind of her correspondent that she addressed. What appeared from time to time in the Record and in the Women's Missionary Magazine, were mainly extracts from private letters, and they derived all their charm and colour from the fact that they were meant for friends who loved and understood her. In the same way she would be chilled by receiving a coldly expressed letter. "I wish you hadn't said Dear Madam," she told a lady at home. "I'm just an insignificant, wee, auld wifey that you would never address in that way if you knew me. I'll put the Madam aside, and drag up my chair close to you and the girls you write for, and we'll have a chat by the fireside."

She could not help writing; it was the main outlet for her loving nature, so much repressed in the loneliness of the bush. Had she not possessed so big and so ardent a heart, she would have written less. Into her letters she poured all the wealth of her affection; they were in the real sense love-letters; and her magic gift of sympathy made them always prized by the recipients. She had no home people of her own, and she pressed her nearest friends to make her "one of the family." "If," she would say, "you would let me share in any disappointments or troubles, I would feel more worthy of your love—I will tell you some of mine as a counter-irritant!" Many followed her behest with good result. "I'm cross this morning," wrote a young missionary at the beginning of a long letter, "and I know it is all my own fault, but I am sure that writing to you will put me in a better temper. When things go wrong, there is nothing like a talk with you…. Now I must stop, the letter has worked the cure." Her letters of counsel to her colleagues when they were in difficulties with their work were helpful and inspiring to the highest degree. On occasions of trial or sorrow she always knew the right word to say. How delicately, for instance, would she try to take the edge off the grief of bereaved friends by describing the arrival of the spirit in heaven, and the glad welcome that would be got there from those who had gone before. "Heaven is just a meeting and a homing of our real selves. God will never make us into new personalities. Everlasting life—take that word life and turn it over and over and press it and try to measure it, and see what it will yield. It is a magnificent idea which comprises everything that heart can yearn after." On another occasion she wrote, "I do not like that petition in the Prayer Book, From sudden death, good Lord deliver us. I never could pray it. It is surely far better to see Him at once without pain of parting or physical debility. Why should we not be like the apostle in his confident outburst of praise and assurance, 'For I am persuaded…'?" Again: "Don't talk about the cold hand of death—it is the hand of Christ."

It was not surprising that her correspondence became greater at last than she could manage. The pile of unanswered communications was like a millstone round her neck, and in these latter days she began to violate an old rule and snatch time from the hours of night. Headings such as "10 P.M.," "Midnight," "8.45 A.M.," became frequent, yet she would give love's full measure to every correspondent, and there was seldom sign of undue strain. "If my pen is in a hurry," she would say, "my heart is not." When she was ill and unable to write, she would simply lie in bed and speak to her Father about it all.

There was a number of friends to whom she wrote regularly, and whose relations to her may be judged from the manner in which they began their letters. "My lady of Grace," "My beloved missionary," "Dearest sister," were some of the phrases used. But her nature demanded at least one confidante to whom she could lay bare her inmost thoughts. She needed a safety-valve, a city of refuge, a heart and mind with whom there would be no reservations, and Providence provided her with a kind of confessor from whom she obtained all the understanding and sympathy and love she craved for. This was Miss Adam, who, while occasionally differing from her in minor matters of policy, never, during the fifteen years of their friendship, once failed her. What she was to the lonely missionary no one can know. Mary said she knew without being told what was in her heart, and "how sweet," she added, "it is to be understood and have love reading between the lines." Month by month she sent to Bowden the intimate story of her doings, her troubles, hopes, and fears, and joys, and received in return wise and tender counsel and encouragement and practical help. She kept the letters under her pillow and read and reread them.

Never self-centred or self-sufficient, she depended upon the letters that came from home to a greater extent than many of her friends suspected. She needed the inflow of love into her own life, and she valued the letters that brought her cheer and stimulus and inspiration. Once she was travelling on foot, and had four miles of hill-road to go, and was feeling very weary and depressed at the magnitude of the work and her own weakness, when a letter was handed to her. It was the only one by that mail, but it was enough. She sat down, and in the quiet of the bush she opened it, and as she read all the tiredness fled, the heat was forgotten, the road was easy, and she went blithely up the hill.

Outside the circle of her friends many people wrote to her from Scotland, and some from England, Canada, and America. Boys and girls whom she had never seen sent her letters telling her of their cats and dogs, of football, and lessons and school. With her replies sometimes went a snake skin, a brass tray, a miniature paddle, or other curio. But it was the letter, rather than the gift, that was enjoyed. As one girl wrote; "You are away out helping the poor black kiddies and people, and just as busy doing good as possible, and yet you've time to send a letter home to a little Scottish girl, a letter fragrant with everything lovely and good, that makes one try harder than ever to do right, and that fills one's heart with beautiful helpful thoughts."

To her own bairns, wherever they were, she wrote letters full of household news and gentle advice. To Dan at the Institute she wrote regularly—very pleased she was when she heard he had been at lectures on bacteria and understood them!—and when Alice and Maggie were inmates of the Edgerley Memorial School she kept in the closest touch with them. Here is a specimen of her letters, written chiefly in Efik, and addressed apparently to Alice:

MY PRECIOUS CHILDREN—I am thinking a lot about you, for you will soon be losing our dear Miss Young; and while I am sorry for myself I am sorrier for you and Calabar. How are you all? and have you been good? and are you all trying to serve and please Jesus your Lord? Whitie has gone to sleep. She has been making sand and yÖÑÖ-ing my bedroom, the bit that you did not finish. Janie has yÖÑÖ-d the high bits, so Whitie is very tired. Janie has gone to stay all night with the twin-mother and her baby in the town where Effiom used to live long ago. One baby was dead, but she is keeping the other, and the chief says, "Ma, you are our mother, but what you have done will be the death of us." But I tell them just to die.

The mother almost died. One child was born dead, and Janie and I stayed all night there. Mary is at Ikot Ekpene. We saw her as we passed in the motor. The whole town came to-day and put splendid beams in the verandah both in front and behind, swept all behind, and put on a corrugated iron roof, did the porch and various other things, and the safe.

Good-bye. Are you well? We are well, through God's goodness. Are you coming soon for holidays? My heart is hungry to see you and to touch your hands. Greetings to Ma Fuller. Greet Ma Wilkie and Mr. Wilkie for me. Greet each other. All we greet you. With much love to Maggie, Dan, AsuquÖ,—I am, in all my prayers, your mother, M. Slessor.

The girls and Dan also wrote regularly to her in Efik—such letters as this:

I am pleased to send this little letter to you. Are you well? I am fairly well through the goodness of God. Why have you delayed to send us a letter? Perhaps you are too busy to write, but we are coming home in a fortnight. If you hear we are on the way come quickly out when you hear the voices of the people from the beach, because you know it will be us. Greet Whitie, Janie, Annie and all, and accept greeting from your loving child MAGGIE.

After her death there was found at Use a bundle of papers, evidently much treasured, labelled "My children's letters."