According to Jung (1963/1989), in the summer of 1898, he was studying in his room, with the door half open to the dining room, where his mother was knitting by the window. A very loud crack, like a pistol, surprised them and the circular walnut, solid wood table beside her had split, from the rim to beyond the center. (pp. 104-105)
About 2 weeks later, Jung (1963/1989) says he returned home in the afternoon and found his mother, his fourteen-year-old sister, and the maid very upset. About an hour earlier they had heard another deafening crack. This time it had come from the direction of the sideboard, a heavy piece of furniture dating from the early nineteenth century. They had already examined it and could not find anything strange. Jung immediately began examining the sideboard and the entire surrounding area. In the interior of the sideboard, in the cupboard containing the bread basket he found a bread knife, with its steel blade broken to pieces. Its handle in one corner of the basket, pieces of the blade in all other corners of the basket. Carl Jung kept the fragments of that knife, until his death. (pp. 105-106)
Little did he realize at the time that in the future he would study these phenomena as a part of mind’s functioning.
According to Jung (1963/1989), the first real crisis in their friendship came in spring 1909, from the following incident. Jung visited Freud in Vienna and asked his opinion on precognition and parapsychology. But Freud was too materialistic and rejected these matters in a way that upset Jung. A strange thing happened then. As Freud was leaving, Jung felt his diaphragm burning and a very loud crack came from the bookcase next to them. When Jung told Freud that this is a perfect example of paranormal phenomenon, he still denied it. Then Jung predicted that in a moment there would be another loud noise. And he was right; a second loud crack came from the bookcase. Freud remained puzzled and this incident raised his mistrust towards Jung. (pp. 155-156)