On 9 May 2018, I graduated on my research of instruments for celestial navigation at the Vrije Universiteit Amsterdam. I started this research some 17 years ago, when I wanted to know which instrument(s) were used prior to the invention of the octant. After having published several articles on the topic I was allowed to start my PhD research at the Vrije Universiteit in Amsterdam in 2012. Now my PhD thesis is ready and printed in a limited edition of 300 copies:

N. de Hilster, Navigation on Wood, Wooden Navigational Instruments 1590-1731: An analysis of early modern western instruments for celestial navigation, their origins, mathematical concepts and accuracies., (PhD thesis, Vrije Universiteit, Amsterdam, May 2018).

In my thesis I explore the relationship between the instruments, their common ancestors, their construction, and performance of instruments in the period from 1590 to 1731. It was in 1590 when the Englishman Thomas Hood created his cross-staff, the first staff type navigational instrument that used the shadow of an attached vane to cast a shadow on one of its scales. His method of shadow casting was soon improved by countryman Thomas Harriot. Although Harriot's way of shadow casting resulted in a great improvement in the quality of the observations, by almost an order of magnitude, both methods of shadow casting remained into use well into the nineteenth century. Examples of instruments using Hood's shadow casting method were the Davis quadrant and the cross-bow quadrant, while examples using Harriot's method were the hoekboog and demi-cross.

The thesis is printed in a limited edition of 300 copies, hardcover, linen backed, with full colour dust cover. It has 815 pages with 324 figures, 47 tables, eight appendices (with additional figures and tables), and four indexes. The first year after my graduation the thesis will be available in print only, after that year as a download through the university's web site as well. Currently only the cover, titlepage, table of contents, and summary are digitally available.

The thesis has been made possible thanks to the generous donations by the following funds:

• J.E. Jurriaanse Stichting;
• Samenwerkende Maritieme Fondsen;
• Stichting dr. Hendrik Muller’s Vaderlandsch Fonds;
• Thijssen-Schoute Stichting.

As the first edition sold out without a decrease in demand a second edition was printed in spring 2020. This allowed to correct for minor errors, to add two footnotes (125a and 1886a), to expand footnote 1667, to add two works to the Secondary sources bibliography (Hilster 2019, Mollan 1995), and to revise the Index of instruments. Otherwise content and numbering have remained unchanged to avoid discrepancies between the first and second edition.

A copy of my thesis can be ordered by clicking here.

Together the funds financed approximately half of the printing costs the first edition.

The second edition was produced at the same standards as the first, but with a new dust wrapper to distinguish it from the first edition and with the correction mentioned above. It was 100% privately funded, as a result the price had to go up.

Current prices:

Edition	ISBN	Price
Second edition	9789082830217	49 euro
First edition (sold out)	9789082830200	n.a.

Shipping will add another 8 euro for the Netherlands, 14 euro for western Europe, 20 euro for the rest of Europe, 30 euro for the rest of the world.

As expected no work can be made without errors. This section lists the errors found so far in the first edition (these have been corrected in the second edition):

p.165: Caption ends in superscript, should be normal script (inv.no. A.1835);

p.203: Caption fig.46: "MDaniel" should read "Daniel";

p.228, Footnote 811: "...no.216 from the Birr Castle collection" should read "...no.217 from the Birr Castle collection";

p.377, Figure 193: caption "demi-cross" should read "demi-quadrant";

p.381: Caption fig.196: "demiquadrant" should read "demi-quadrant";

p.389: Caption fig.199 should have reference "(illustrations by the author)";

p.449, Figure 224: caption should read "Standard deviation per observer of the human perception experiment.";

p.489: Caption fig.252: "kamal" should be cursive;

p.490: Caption fig.253: "kamal" should be cursive;

p.615, Footnote 1799: reference should be: S. Purchas, Purchas his Pilgrimes in Five Bookes, (London, 1625), f.1213r;

p.666, "The Haven-Finding Art, A History of Navigation from Osyssseus to Captain Cook" should read "The Haven-Finding Art, A History of Navigation from Odysseus to Captain Cook";

p.667: Entry "Waters, D.W., ‘science and the Techniques...": first character of science should be upper case: "Waters, D.W., ‘Science and the Techniques...";

p.673, Caption of Figure 3 should read: "The Mariner’s Astrolabe (Cortés 1551).";

p.703, “(e.g. 25/65” means the smaller radius arc contains 25 degrees, the larger radius arc 65 degrees)." should read "(e.g. “25/65” means the larger radius arc contains 25 degrees, the smaller radius arc 65 degrees)";

p.716, item 217: "Birr Castle UK" should read "Birr Castle, Republic of Ireland";

p.766, "Garmin Extrex Vista" should read "Garmin eTrex Vista";

p.801: The second edition has a new Index of Instruments with many additions.

My knowledge on the subject still expands and below I reserved some space for the things I found after the printing of my thesis and which I wish to share with the readers.

- p.49 (added to the second edition): here I state that "As far as we know no part nor the whole book was ever published in print...", but in August 2018 I acquired D.B Quinn, A.M. Quinn, 'The English New England Voyages 1602-1608', in: The Hakluyt Society, Series II, Vol. 161., (London, 1983), in which I found on pp.232-235 short sections of the preface (ff.6-9) and the introduction (ff.201-204) to 'The fifte booke concerning fortification'. On pp.236-241 Quinn and Quinn also show six facsimile reproductions of the 'foundations and bullwarkes' (ff. 264v, 247v, 248v, 249v, 250v and 251v). It has to be noted that the transcription by Quinn and Quinn is mixed up on several places. On page 233 the transcription of Waymouth's work suddenly continues with Quinn and Quinn's own writing (last sentence of the first paragraph, the section starting with "a further opportunity to attempt it..."). The second line on page 234 suddenly jumps (after "...not with standing") from line 19 of folio 203 (f.203:19) to f.7:17. Likewise at the fourth line from the bottom of page 234 the transcription jumps back from f.9:7 to f.203:19. [a note has been added to the second edition]

- p.518, n.1667 (added to the second edition): The number of casualties in the Shovel disaster is mentioned to be somewhere between 1600 and 2000. In a writing in issue 79 of the Observator of 3 December 1707 can be read that "... we had Advice from Portsmouth, of Sir Geo. Bing's [Sir George Byng, 1st Viscount Torrington, who was present during the disaster] Arrival with the melancholy News, That Sir Cloudsly Shovel, in the Association, a second Rate, of 680 Men, and 96 Guns, was cast away on the Rocks call'd, The Bishop and his Clerks, off of Scilly; that the St. George did also beat against the same Rocks; that the Eagle, a third Rate, of 400 Men, and 70 Guns; the Rumney, a fourth Rate, of 280 Men, and 54 Guns; and the Firebrand Fire-ship, of 45 Men, and 8 Guns, were also lost." The St. George escaped to safety, without any losses. Totalling the figures of the four lost ships we get to a loss of 1405 men, considerably less than the modern figure of 1600-2000, but still an impressive amount and a great tragedy. [a note has been added to the second edition]

pp. 661, 704-818 (added to the second edition): Some of the instruments listed in Appendix C - Davis Quadrants around the World have the indication "Charles Mollan" followed by an Ex... number in the Remarks column. These entries refer to the following work which accidentally was omitted from the bibliography: Mollan, R.C., Irish National Inventory of Historic Scientific Instruments: Report, (Dublin, 1995). [a note has been added to the second edition]