Instruments / Charts

The English may have arrived a bit late on the scene where publishing about the use and design of technical and mathematical instruments for navigational purposes is concerned. However, they soon caught up and started not only improving existing inventions, such as for example the astrolabe of Gemma Frisius (Jemme Reinerszoon) and Gerardus Mercator’s (Gerard de Kremer) map projection, but also designing their own instruments.50

The first English author to discuss such nautical instruments in print was the mathematician and land surveyor John Blagrave, who published various works starting in 1585 with The mathematical ievvel [...] so called: in that it performeth with wonderfull dexteritie, whatsoeuer is to be done, either by quadrant, ship, circle, cylinder, ring, dyall, horoscope, astrolabe, sphere, globe, or any such like heretofore deuised [STC 3119], in which he discussed an astrolabe of his own invention, illustrated with woodcuts made by Blagrave himself.51 The astrolabe was an instrument that had many possible uses, such as calculating the position of the stars, the sun and

48 _{Morgan, Basil, ‘Hawkins, Sir John’, ODNB.} 49 _{Loades, ‘Hawkins [Hawkyns], Sir Richard’, ODNB.} 50 _{Waters, The Art of Navigation, 166 and 295.} 51

Thompson, ‘Blagrave, John’, ODNB; Taylor, The Mathematical Practitioners, 181 and 327; Waters,

the moon and hence also determining time and latitude. Blagrave’s last publication, which appeared in 1609, concerned sundials and was entitled The art of dyalling in two parts [STC 3116].52 William Barlow, a clergyman with a huge interest in mathematics and its application in navigation and also tutor to Prince Henry of Wales, published a comprehensive work in 1597 entitled The navigators supply. Conteining many things of principall importance belonging to nauigation, with the description and vse of diuerse instruments framed chiefly for that purpose [STC 1445].53 This book, which discussed Blagrave’s ‘jewel’ as well as a number of other new and improved instruments, was dedicated to the second earl of Essex, Robert Devereux. The use of the ‘jewel’ had also been included by Blundeville in his Exercises (see p. 18). Blundeville himself, however, focused on maps in his 1589 A briefe description of vniuersal mappes and cardes, and of their vse [...] for traueilers by land or sea [STC 3145], which was reprinted in the 1597 second edition of the Exercises [STC 3147]. Another work by him, The theoriques of the seuen planets [STC 3160] from 1602, included an addition entitled The making, description, and vse, of two most ingenious and necessarie Instruments for Sea-men [STC 3160], which discussed some of William Gilbert’s inventions.54 An appendix to this addition was written by Wright, giving the reader a practical explanation of how to use a table devised by Henry Briggs on Gilbert’s advice (PP4v-PP4r), showing just how close a network the mathematicians formed.

Celestial globes were described in 1585 by Oxford-based physician Charles Turnbull in A perfect and easie treatise of the vse of the cœlestiall globe: written aswell

52 _{Taylor, The Mathematical Practitioners, 339.}

53 _{McConnell, ‘Barlow, William’, ODNB; Taylor, The Mathematical Practitioners, 177 and 334-335,} Waters, The Art of Navigation, 216-217.

for [...] as the practise of our countriemen, which bee exercised in the art of nauigation

(repr. 1597) [STC 24337-24338]. Though Turnbull had no particular interest in navigation himself but rather in astronomical observation, the use of globes was important for navigators, as indicated in the title quoted above.55 Globes were also discussed by the mathematician Thomas Hood and the astronomer Robert Tanner. Hood, a teacher of mathematical navigation, wrote two works concerning them, in 1590 The vse of the celestial globe in plano, set foorth in two hemispheres [STC 13697] and two years later The vse of both the globes, celestiall, and terrestriall [STC 13698].56 Three other instruments of his own design appeared in the 1590 The vse of the two mathematicall instruments, the crosse staffe, and the Jacobs staffe (repr.1596) [STC 13699-13701] and the 1598 The making and vse of the geometricall instrument, called a sector [STC 13695]. While the Jacob’s Staff was meant for surveying land, the Cross-staff was used at sea to determine latitude and Hood presented that part of the work to Charles Howard, then Lord High Admiral, first in manuscript but soon after, because of great demand, in print.57 In Hood’s work, the sector was also described primarily as a surveying instrument but in itself it was a type of compass that made it easier to solve mathematical problems and could as such be used in aspects of navigation and gunnery. After writing A mirror for mathematiques [...] for geometricians [...] saylers [...] astronomers and astrologians [STC 23674-23674.5] in 1587, which described the making and use of an astrolabe, astronomer Robert Tanner discussed the use of the globe in A briefe treatise for the ready vse of the sphere [...] as well cœlestial as terrestiall [STC 23671], published in 1592, which was reworked in

55 _{Taylor, The Mathematical Practitioners, 179-180.} 56

Higton, ‘Hood, Thomas’, ODNB;Taylor, The Mathematical Practitioners, 179 and 330. 57 _{Taylor, The Mathematical Practitioners, 329-330.}

1616 as A brief treatise of the use of the globe celestiall and terrestriall (repr. 1620) [STC 23672-26373].58

Works on instruments continued to be published into the early seventeenth century. Arthur Hopton, an almanac maker and instrument designer, published two textbooks, namely Baculum geodæticum sive viaticum. Or the geodeticall staffe [STC 13776], published in 1610 with a dedication to Robert Cecil, and a year later Speculum topographicum: or the topographicall glasse [STC 13783], dedicated to the Lord Chancellor, Thomas Egerton.59 The ‘geodeticall staffe’ could be used for a variety of measurements useful for surveyors, navigators and seamen, while the topographical glass was another type of calculating instrument used for measuring angles.60 Edward Wright, in his role as royal tutor to Prince Henry, wrote The description and use of the sphære (1613, repr. 1627) [STC 26021-26022], intended to accompany an instrument built specifically for his pupil.61 The mathematician and astronomy professor Edmund Gunter, a friend and colleague of Briggs, is the author of the substantial 1623 De sectore & radio. The description and use of the sector [STC 12521-12523], which also included other (improved) mathematical instruments of his own design such as a cross- staff and an alternative to the traditional backstaff.62 It was originally written in Latin until it became so popular that Gunter found it easier to have it printed, and this in English.63 Finally, John Aspley, student of physics, wrote Speculum nauticum: a looking glasse, for sea-men: wherein they may behold a small instrument called the plaine scale [STC 861], the scale being a type of ruler used to crudely measure distance

58

Waters, The Art of Navigation, 166-167 and 212-213.

59 _{Capp, ‘Hopton, Arthur’, ODNB; Taylor, The Mathematical Practitioners, 200.} 60 _{Waters, The Art of Navigation, 317-318.}

61 _{Apt, ‘Wright, Edward’, ODNB.} 62

Higton, ‘Gunter, Edmund’, ODNB.

and departure.64 First published in 1624, it was reprinted and re-edited another eight times before the end of the century, with a dedication to the masters and governors of Trinity House.