From the time I was a small child, you diligently walked with me in fields and forests. Beyond Bragernes you ran with me, and when the road became heavy and long for me, you faithfully carried me on your back. From then until now I have loved forests, mountains, and meadows with the same childish fervour. I remember well how many times I sat on your lap and listened when you sang to me. From then until now I have loved the sound of our music with the same childish fervour. I grew older, so the Norman heart beat within me, and you described in golden writing the achievements of our people. From the old Viking raids to when my grandfather came along and fought for our young freedom.

... it is obvious that we have had to put a special effort into the historical part of the answer. But here we encountered a difficulty over which the student at our university is not master. Our university library, as an institution that is still quite young compared to foreign libraries, cannot possibly provide all the aids necessary to the researcher for such an investigation. We must certainly be very satisfied with the circumstances that the not entirely insignificant literary apparatus possesses. But fortunately we have not been able to supplement this in one important point. During a study stay in Copenhagen in the summer of 1876 we have, as far as time permitted, taken advantage of the favourable opportunity offered by the larger libraries there ...

It is a truth, repeated to the point of triviality, that no progress in the course of history has occurred suddenly; there is no leap in development; all reforms come well prepared. The recognition of this might, to a superficial consideration, seem to take away some of the greatness of the individual people to whose names these reforms have most often been attached; but in reality the close examination of those preceding advances, which contain in essence the thoughts which these people had fixed, will confirm their greatness much more, since it is thus better understood. The examination will show the vagueness and timidity of those first beginnings, which resist leaving the beaten paths; by revealing how new ideas gain space and spread here and there, it shows us even more generally and clearly the reverence that surrounds the existing, and at the same time, as it makes us aware that an education is needed before the individual can carry out his reform. It teaches us to recognise precisely that which, by encountering obstacles over such long periods, gives the best testimony to its true significance, to whom the final victory of progress is due.

The truth of these considerations will make such an investigation a duty for anyone who intends to determine with what right this or that progress is attributed to a given individual; but the subject at hand makes it, for several reasons, even more necessary to undertake such a retrospective.

Poncelet's importance is linked to the emergence of modern geometry. It is well known that traces of modern-geometric subjects, both theorems and problems, are found already among the ancients. It is therefore easy to believe, and can be heard asserted, that a modern-geometric way of thinking was already the property of the ancients, that the perspective projection or similar means of proof were known to them. This is, in our opinion, on the one hand an overestimation of the geometry of the ancients, and on the other a misunderstanding of its character, which it is therefore important to demonstrate and correct.

We have read with pleasure this book, which is based on careful studies of the geometrical works from the first half of the century, and which was prepared by an author with an awakened mind for the significance of the rich and fruitful thoughts that emerged and developed in these works, and with a sound and clear judgment. We then also agree with the author in the most important of his results, thus in allowing Poncelet - to whom physics owes the introduction of the pervasive use of the concept of work - to occupy the main place among the founders of projective geometry. However, we are inclined to believe that the richness and significance of what Poncelet had already brought, has instilled in the author too strong a feeling of the necessity with which the later advances had to emerge from the new ideas introduced by Poncelet, and therefore allowed him to see Steiner's and Chasles's extraordinary merits precisely in the fundamentals of projective geometry (conic sections) in a somewhat too weak light. In such a case, it is the author as well as Chasles, about whom he believes that in his historical works, at Poncelet's expense, he emphasises too strongly what was already owed to Monge and his school as well as Carnot before Poncelet. This reproach is not unfounded, if Chasles' perception is natural in a man whose greatest thoughts were not awakened by Poncelet's works but pointed back to their common predecessors. How well, in particular, Monge and his school had really prepared the actual projective geometry, can be seen from the fact that such a Fundamental Theorem as the one about the double generation of the skewed Hyperboloid is found in Monge's drawing rooms, without the discoverer being known, and from the early appearance of such theorems as them, which is due to Brianchon who we agree with the author, that Chasles could have given a more outstanding place among Monge's Disciples than he does.

We have looked here at a small sample of the discussions we have had with the author's thoughts. That such discussions are constantly evoked during the reading should testify well to the lively presentation of the extensive material that the book contains.

Several geometers, particularly Poncelet, but also Plücker, Chasles, and the other founders of projective geometry, have advanced geometry by borrowing, so to speak, new axioms from analysis. It may be debatable whether the science thus constituted can still be called Pure Geometry; but no one can deny that the introduction of these methods constitutes genuine progress. While the aforementioned principles, borrowed from analysis, are related to the law of continuity, it is also possible to make similar use of another principle of algebra, which we will outline by then applying it to various examples.

These two positions gave him a heavy teaching load, so that his scientific output in his later years was essentially limited to biographies of Norwegian mathematicians, a field in which he had otherwise made great contributions.

In his diary Carl noted that during 1893, Holst visited the Størmer residence once every week. Even for many years later, Holst and Carl met regularly. ... During university studies in mathematics Carl considered him [Holst] the best lecturer at the University.... Several documents clearly show that he was a popular teacher.

There was a national programme behind this effort: Holst wanted to preserve the orally transmitted Norwegian children's poetry. In his writing, Holst emphasised everyday language and Norwegian pronunciation.

No other man has ever touched me as deeply as Elling when I was young, and I am thankful to have known him. He was such a special person.

It often arouses astonishment among outsiders when mathematicians use such words as "elegant" about mathematical proofs and operations. I dare to go further and say that there was something "lovable" about Elling Holst's mathematical works, and thereby mean to emphasise a quality that is also mathematically admirable. Just as in his children's books, which one would not hesitate to characterise in the manner mentioned above, he uses his fertile imagination and artistic abilities to bring out what can be understood by and delight children, so he also uses his fertile geometric imagination - an artistic ability that is used in all creative geometric work - to invent such details that would appeal to mathematicians, arouse their attention and make them share his own warm interest in the methods used and encourage them to use these in other cases as well.

Let me highlight one aspect of Elling Holst's personality that has been of the greatest importance for his work as a teacher. It is his ability to track down among his students those who showed distinct mathematical aptitude. When he found such, he was tireless in encouraging and helping them with advice and action. He sought to inspire them to work independently and rejoiced with them when they came to him with their scientific findings. He followed them through life with the greatest fidelity and disinterestedness and, idealist as he was, he taught them to view science ideally, to cultivate it for its own sake without regard to material advantage, to look forward and upward in order to strive to reach the highest!