We need not trouble ourselves with the speculations of Alexander the Great, Aristotle, and Pliny concerning "underwater" activities. Their active minds gave consideration to the problem, but mainly as to the employment of divers. Not until the first part of the sixteenth century do we find any very specific reference to actual underwater boats. That appears in a book of travels by Olaus Magnus, Archbishop of Upsala in Sweden. Notwithstanding the gentleman's reverend quality, one must question somewhat the veracity of the chapter which he heads:

"Of the Leather Ships Made of Hides Used by the Pyrats of Greenland."

He professed to have seen two of these "ships," more probably boats, hanging in a cathedral church in Greenland. With these singular vessels, according to his veracious reports the people of that country could navigate under water and attack stranger ships from beneath. "For the Inhabitants of that Countrey are wont to get small profits by the spoils of others," he wrote, "by these and the like treacherous Arts, who by their thieving wit, and by boring a hole privately in the sides of the ships beneath (as I said) have let in the water and presently caused them to sink."

Leaving the tale of the Archbishop where we think it must belong in the realm of fiction, we may note that it was not until the beginning of the seventeenth century that the first submarine boat was actually built and navigated. A Hollander, Cornelius Drebel, or Van Drebel, born in 1572, in the town of Alkmaar, had come to London during the reign of James I., who became his patron and friend. Drebel seems to have been a serious student of science and in many ways far ahead of his times. Moreover, he had the talent of getting next to royalty. In 1620 he first conceived the idea of building a submarine. Fairly detailed descriptions of his boats—he built three from 1620-1624—and of their actual use, have been handed down to us by men whose accuracy and truthfulness cannot be doubted. The Honorable Robert Boyle, a scientist of unquestioned seriousness, tells in his New Experiments, Physico-Mechanical touching the Spring of the Air and its Effects about Drebel's work in the quaint language of his time:

But yet on occasion of this opinion of Paracelsus, perhaps it will not be impertinent if, before I proceed, I acquaint your Lordship with a conceit of that deservedly famous mechanician and Chymist, Cornelius Drebel, who, among other strange things that he perform'd, is affirm'd, by more than a few credible persons, to have contrived for the late learned King James, a vessel to go under water; of which, trial was made in the Thames, with admired success, the vessel carrying twelve rowers, besides passengers; one which is yet alive, and related it to an excellent Mathematician that informed me of it. Now that for which I mention this story is, that having had the curiosity and opportunity to make particular inquiries among the relations of Drebel, and especially of an ingenious physician that married his daughter, concerning the grounds upon which he conceived it feasible to make men unaccustomed to continue so long under water without suffocation, or (as the lately mentioned person that went in the vessel affirms) without inconvenience; I was answered, that Drebel conceived, that it is not the whole body of the air, but a certain quintessence (as Chymists speak) or spirituous part of it, that makes it fit for respiration; which being spent, the remaining grosser body, or carcase, if I may so call it, of the air, is unable to cherish the vital flame residing in the heart; so that, for aught I could gather, besides the mechanical contrivances of his vessel, he had a chymical liquor, which he accounted the chief secret of his submarine navigation. For when, from time to time, he conceived that the finer and purer part of the air was consumed, or over-clogged by the respiration and steam of those that went in his ship, he would by unstopping a vessel full of this liquor, speedily restore to the troubled air such a proportion of vital parts, as would make it again, for a good while, fit for respiration whether by dissipating, or precipitating the grosser exhalations, or by some other intelligible way, I must not now stay to examine, contenting myself to add, that having had the opportunity to do some service to those of his relations that were most intimate with him, and having made it my business to learn what this strange liquor might be, they constantly affirmed that Drebel would never disclose the liquor unto any, nor so much as tell the nature whereof he had made it, to above one person, who himself assured me what it was.

This most curious narrative suggests that in some way Drebel, who died in London in 1634, had discovered the art of compressing oxygen and conceived the idea of making it serviceable for freshening the air in a boat, or other place, contaminated by the respiration of a number of men for a long time. Indeed the reference made to the substance by which Drebel purified the atmosphere in his submarine as "a liquor" suggests that he may possibly have hit upon the secret of liquid air which late in the nineteenth century caused such a stir in the United States. Of his possession of some such secret there can be no doubt whatsoever, for Samuel Pepys refers in his famous diary to a lawsuit, brought in the King's Courts by the heirs of Drebel, to secure the secret for their own use. What was the outcome of the suit or the subsequent history of Drebel's invention history does not record.

Throughout the next 150 years a large number of inventors and near-inventors occupied themselves with the problem of the submarine. Some of these men went no further than to draw plans and to write out descriptions of what appeared to them to be feasible submarine boats. Others took one step further, by taking out patents, but only very few of the submarine engineers of this period had either the means or the courage to test their inventions in the only practicable way, by building an experimental boat and using it.

In spite of this apparent lack of faith on the part of the men who worked on the submarine problem, it would not be fair to condemn them as fakirs. Experimental workers, in those times, had to face many difficulties which were removed in later times. The study of science and the examination of the forces of nature were not only not as popular as they became later, but frequently were looked upon as blasphemous, savouring of sorcery, or as a sign of an unbalanced mind.