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### Navigation: The Method of the Marteloio (p. 48a)

This is the third page of Michael's demonstration of the *marteloio* method for navigating "mentally." Here he explains how to use a table to calculate the distance back to an intended course after his ship has been blown off course in four different directions of 100 miles each. In the last paragraph, Michael begins an explanation of how to use the table to calculate the distance to land sighted west of his course.

See enlargement:

+ Ihesus + E per un'altra raxion la mia via e per ponente e non di posso andar, e von quarta de ponente al garbin mia 100. El vento va avan- ti, e von intro ponente garbin mia 100. El vento va avanti, e von ala quarta de garbin inver lo ponente. El vento va avanti, e von per garbin mia 100. Adomando quanty mia voyo venir per maistro ch'io vegna ala mia croxe, e questo e lo muodo, e quanto avero avanzado. E diremo che xe l'alargar de quarta una, sera 20, e de 2/4 38, e de 3/4 55, e de 4/4 71. Azonti tutti insieme serano 184. E puo dire- mo che lo ritorno de 4/4 sono 14. Moltipicha' 184/10 chon 14/1 fano 2576, partidi per 10 fano mya 257 6/10. E tanti mya averi chaminado per venir ala croxe. E che avero avanzado che xe l'avanzo di ritorno de quarte 4? Sono 10, moltipichadi per 184/10 fano 1840, partidi per 10 serano mia 184. E po' diremo che xe l'a- vanzo di largar. De quarta 1a sono 98, e 2/4 92, e 3/4 83, e 4/4 71. Asumadi fano 344, azonzi chon 184, fano 528. E tanto averai avanzado. E chi tte domandase: "Che avero Per un'oltra raxion una tera me sta per ponente la sera, e non dicho quanto mia la notte von. La notte von per maistro mia 41 8/10 e la maitina me sta quel teren intro ponente garbin. Quanti mie son alargo mo' che me sta el teren intro ponente garbin, e quanti mia era alargo la sera quando me steva per po- nente?" Tu die far per questo muodo e dir che m'alargo per 2/4 38/10, e lo ritorno de 6/4 son 11. Adoncha moltipicha 38 fia //

+ Jesus + And by another calculation, my course is to the west and I cannot go, and we go 100 miles west by south. The wind goes on, and we go toward west southwest 100 miles. The wind goes on, and we go southwest by west. The wind goes on, and we go southwest 100 miles. I ask how many miles I want to go northwest so I come to my course, and this is the way, and how much I will have advanced. And we will say that the distance off course of one quarter will be 20, and of 2 quarters 38, and of 3 quarters 55, and of 4 quarters 71. Added all together it will be 184. And then we will say that the return of 4 quarters is 14. Multiply 184/10 with 14/1 makes 2576, divided by 10 makes 257 6/10 miles. And that is how many miles you will have traveled to get to the course. And what will I have advanced on the return of 4 quarters? It is 10, multiplied by 184/10 makes 1840, divided by 10 will be 184 miles. And then we will say what is the ad- vance on the distance off course. From one quarter it is 98 and 2 quarters 92 and 3 quarters 83, and 4 quarters 71. Added together they make 344, added to 184, makes 528. And this much you will have advanced. And if someone asks you: "What will I have As another calculation, a land is west of me in the evening and I can't say how many miles we go in the night. In the night we go northwest 41 8/10 miles and in the morning that land is toward west southwest. How many miles is the distance now that the land is toward west southwest, and how many miles was it distant in the evening when it was to my west?" You should do it this way and say that my distance off course for 2 quarters 38/10 and the return of 6 quarters is 11. Therefore multiply 38 by