This volume consists of brief notes in plain language on a variety of scientific matters. I speak of new discoveries, real or so-called by mistake; of old well-established facts and explanations of strange occurrences which are more familiar to men of science than to people who have not had the time and opportunity to ascertain what is, and what is not proved and known about Nature and her ways. I do not address my reader from the professor’s chair, but from an easy chair. Just as in the club or my friend’s smoking-room, I might talk of these things, so do I propose to talk here. My hope is that what I have to say will interest those who are not experts in science, and yet have a desire for trustworthy information and opinion on the vast variety of topics which come up day by day for consideration and discussion, and can only be explained or rightly understood by the aid of that systematised knowledge which is called science.

Science and the scientific point of view have a very wide, indeed, an unlimited range. Though the making of discoveries of real importance and the full understanding of the steps by which they are made involves, as a rule, long study and special training, yet there is a vast deal of healthy excitement and pleasure connected with the progress of science, in which all can share by receiving, as it were, messages from the front. By contributing true records and observations of fact which serve, in however small a way, as ammunition and material of war for the use of the fighting line, we can all help and take part in the advance of science.

A great feature of what is called science is that it is true. The actual result achieved by science is the record of “that which is”—it can be examined, tested, and proved. But science does not merely collect accurate records of fact. In order to discover new things, new relations, and hidden causes she has to make use of guesses and flights of imagination. The “hypotheses” or guesses are not wild ones, but reasonable suppositions based on careful consideration of existing knowledge. They are never mistaken by trained workers in science for “facts,” nor put forward as such. On the contrary, they are tested and so confirmed or rejected by experiment or trial. Hence the necessity of accuracy in observation for the purposes of science; hence the proverbial “scientific accuracy.” It is of no use to form a guess based upon erroneous statements. It is mere waste of time to accept and build theories upon loose wonder-mongers’ gossip. And, further, the evidence which you obtain in order to confirm or dismiss your “guess” must be equally beyond suspicion as to its accuracy. It must be an observation of fact free from prejudice and illusion.

Your guess, if proved to be true, adds to the solid record of science new facts and new proofs of relationships, which again lead on the imagination of men of science to new guesses, and so to new confirmation or rejection, and to the growth of the vast record of accurate knowledge. To seek out in the endless whirling complexity of things which surround us in earth, sky, and sea, the truth, the knowledge of “that which is,” of the relation of these things to one another as cause and effect and their action and influence on ourselves—this is the aim of science. To substitute real understanding and the power of control of the surrounding world for the misleading and cruelly harmful conceptions existing in the minds of simple unskilled mankind—this is the daily achievement of science.