 The book was called "Perioder i Børns Vækst og i Solens Varme", and here he presented his idea, that the factor that caused the variations in the growth of the children and in nature as such in some way was related to the variations in the heat of the sun.His discoveries became well known not only in Denmark, but also internationally, and his book was also translated into German.In 1884 he had also held a lecture on a scientific conference in Copenhagen, attended by scientists from all over the world.