That so important an instrument as a telescope or spy-glass is rarely mentioned in books on navigation or in sea journals seems strange. It is exceedingly difficult to obtain information of any being taken to sea, although one would think a spy-glass would be about the first aid on shipboard especially when skirting the coast. Telescopes did not become of practical use, even if the principle had been known, until they were made in Holland in 1608. It is at least certain that Columbus did not have one and probably there was none on the Mayflower, although its passengers had recently come from Holland where telescopes were invented a few years before. So far no references to them have been found in a rather casual examination of old log-books.

In the Marine Room Collection of the Peabody Museum at Salem, is a spy-glass four feet long, octagonal in form, two and one-half inches in diameter, with a short focusing tube. It was taken from a British prize vessel off the coast of Ireland, in 1779, by Capt. James Barr in his Salem privateer. Another glass of similar form, but longer and with a mahogany case, was used on a United States naval vessel about 1815. The spy-glass, familiar to everyone, in two or three sections, was used at sea through the first half of the nineteenth century and is often seen tucked under the left arm, in the portraits of ship-masters brought home from foreign ports. Many of these were excellent instruments, especially those from Dollond of London. There is also in the Salem collection a rude telescope or spy-glass five and one-half feet long with a copper case about three inches in diameter looking precisely like a section from a house water-conductor. It focuses by a small upper sliding section, fitted like a stove funnel. This glass was brought from Nagasaki, Japan, by a Salem ship-master about 1865. It had been used there to observe vessels coming into the harbor. It may be Dutch and it is evidently very old.

SEXTANTS IN PEABODY MUSEUM, SALEM

1. “Bradford London.” Brass frame and silverscale arm 14 inches long, ca. 1815, used by Capt.George Bailey before 1840.2. “L. Bleuler, London.” Ebony frame, ivoryscale, brass arm 14 inches long, ca. 1820, came fromPlymouth, Mass.

3. “G. Gowland 76 Castle St. Liverpool.” Used by David Livingstone in his Africanexplorations and after his death sold at Zanzibar by order of the Royal GeographicalSociety and bought by Capt. William Beadle, of Salem, and used on some of hisvoyages.

The speed of a vessel was first obtained by throwing overboard a floating subject at the bow and noting the time elapsed when it passed an observer at the stern. From this the log line with “knots” was derived, with the fourteen and twenty-eight seconds sand glasses to record speed. A “knot” indicates a geographical or sea mile which has been standardized at 6080 feet; the land or statute mile is 5280 feet, therefore, if a vessel is said to be sailing at the rate of thirteen knots, a railroad train going at the same speed would be running at the rate of fifteen miles an hour. The term “knot” is used solely to indicate rate of speed; the distance covered is always stated in nautical or sea miles. “Heaving the log” meant throwing out from the stern of a vessel a small float attached to a line running from a reel held clear of the rail, the float remaining stationary in the water. At the instant the log is “heaved” a sand glass is turned. On the line are knots (hence the term), pieces of marline or rags tied through the strands and spaced the same fraction of a mile apart,—above forty-six feet and six inches,—which twenty-eight seconds is the fraction of an hour,—about one one-hundred and twenty-eighth. Therefore, using a twenty-eight seconds glass and checking the line the instant the sand runs out, the number of knots and fractions paid out on the line will at once indicate the number of sea miles per hour which the vessel is going. This, of course, is doubled if the fourteen-seconds glass is used, which is done when the vessel is going very fast.

The old log lines have been superseded by many forms of the “patent log” and the museum is indeed fortunate which possesses an original log line, reel and float in perfect condition. There is an excellent example in the museum collections of the Marblehead Historical Society. Once discarded, the lines were soon used to tie up packages and the reels and floats were thrown away. The patent log with its revolving blades, now universal, was devised by Humfray Cole in 1578; it was improved by various persons from time to time but, strange to say, did not come into general use for nearly three centuries. The rotating blades in the water record the rate on an indicator on the vessel which may be read at any time. So far, the earliest reference to the use of a device of this sort among our New England navigators is the “Gould’s patent log” used by Captain George Crowninshield on his famous yacht Cleopatra’s Barge during the voyage to the Mediterranean in 1817.

Charts were made in very ancient times but they were crude and almost useless. The first nautical maps appeared in Italy at the end of the thirteenth century, and it is said that Bartholomew Columbus brought the first one to England in 1489. The close of the sixteenth century saw many map makers at work, including Gerard Mercator whose name is perpetuated in the familiar scale charts in our geographies known as “Mercator’s projection” which were the sea charts in general use. Globes were carried on ships in preference to charts in the early days and what is known as “great circle” sailing was evolved from them. Davis describes it in 1594 and it is possible that Cabot knew of the theory a century before. Such a simple instrument as a parallel ruler was not invented until late in the sixteenth century and tables of logarithms and Gunter’s scale by which navigators make all their calculations were not known until the year the Mayflower sailed.

During the first century following the settlement of New England it is probable that the small coasting and fishing vessels were navigated by dead reckoning and not venturing far beyond the sight of land a compass was the only instrument carried. But the larger vessels sailing from Boston, Salem, Portsmouth, Newport and other ports on voyages to the West Indies, England and Spain, it would seem should have carried instruments with which observations could be made to obtain their approximate position. Mr. George Francis Dow has searched the early probate records of Essex County coast towns between 1634 and 1680, a period of nearly fifty years, and finds but thirteen references to nautical instruments in inventories and wills. Sometimes they are listed as “marriners instruments” and in one case a quadrant is valued at £1. Robert Gray of Salem, who died in 1661, possessed a “quadrant, a fore-staffe (cross-staff), a gunter’s scale, and a pair of Compasses.” John Bradstreet, who died at Marblehead the previous year, owned “3 small sea books” valued at £1. 6s. The inventory of the estate of Jonathan Browne of Salem, who died in 1667, discloses a “fore-staff,” and that of the estate of John Silsby of Salem, taken in 1676, lists “marriners instruments and callender, 14s.”

In a very detailed inventory made in Salem before a notary publick on Nov. 4, 1702, of the equipment of the ship Province Galley, 90 tons, owned by Roger Derby, the only instruments for navigation that appear are “Two Compasses, two ha[lf] ho[ur] glasses, a ha[lf] Watchglass, a ha[lf] minute glass ... a hand lead line, a deep sea lead line.”