Description

José Ignacio de la SIERRA.

Manuscript, [Spain, perhaps Málaga, circa 1815].

 

José Ignacio de la Sierra was a career Spanish naval officer who was trained as a navigation specialist, becoming a ‘piloto’ (pilot).  With the rank of ‘Segundo Piloto’, he served in Uruguay and Argentina as part of the Royalist (Spanish) forces during the Campaña Naval de 1814, one of the two decisive operations of the Argentine War of Independence.  There, Sierra was the commander of the gunboat Lima in the squadron of Captain Jacinto de Romarate, playing a key role in their victory at the Battle of Arroyo de la China (March 28, 1814), fought near the city of Concepción del Uruguay.  While the Royalists thrashed the Argentines at the Arroyo, they lost the overall campaign.  Sierra is recorded as accompanying Captain Romarate on his return to Spain, whereupon they arrived at Málaga, aboard the merchant frigate Perla, on April 3, 1815.  Subsequently, Sierra worked his way up the ranks, becoming a Frigate Captain in 1839.

 

At some point around the time of Sierra’s return to Spain from South America, he wrote the present work which endeavours to be a comprehensive, practical guide to maritime navigation.  The dating attribution relies on the fact that the title mentions that Sierra held the rank of ‘Segundo Piloto’ at that time, while the latest date given in his statistical charts regarding recorded (as opposed to predictive) data is ‘1813’.

 

At its essence, Sierra’s work seeks to update, streamline and modernize Jorge Juan y Santacilia’s Compendio de navegación para el uso de los cavalleros Guardias Marinas… (Cadiz, 1757), one of the most internationally revered 18^th century works of its kind.  Juan was a legendary mathematician, astronomer and naturalist, who was most famous for co-executing an arc measurement of the Equator in South America as part of the French Geodesic Mission to the Equator (1735-44).

 

To be clear, Sierra’s present manuscript is an original work, as while it derives some of its structure (including some section titles) and some passages from Juan’s tome, it features a great deal of novel content predicated upon Sierra’s own professional experiences.  Notably, it employs different practical examples, or case studies, of the practical applications of theories, many different diagrams, as well as updating chronologically sensitive data (i.e., solar declination tables, etc.) to the contemporary times.  Not to detract in any way from Juan’s masterpiece, but by 1815 its style would have been considered rather Baroque, or verbose, while here Sierra provides a refreshingly crisp delivery, with a fine economy of expression, in line with his times.

 

With the present work, Sierra breathe new life into a classic of maritime scientific literature, making it relevant for his generation of pilots.  The quality of the presentation of the manuscript is extraordinarily high, as the penmanship (in black pen with headings in red) is unusually crisp and elegant, seeming mimicking fine engraving, and must had taken many days of painstaking effort to physically produce.  Its beautiful watercolour title, featuring a ship of sail, is an uncommon feature for such a work, while its numerous diagrams and statistical tables are drafted by an amazingly skilled hand.  While the manuscript is seemingly unrecorded, Sierra clearly intended it for publication.

 

Focussing on the content, it should be noted that 24 points in the text correspond to the diagrams that appear on the three final (folding) leaves, while some sections are illustrated with copious geometrical diagrams.

 

In his introduction “Compendio de Navegacion” pp. 1-2, Sierra, echoing Jorge Juan y Santacilia, writes:

 

“Navigation is the art that teaches how to steer and navigate ships from one place to another on the surface of the waters.  They are divided into theory and practice. Theory is the science that teaches the rules and precepts necessary for this art, and practice is putting these precepts into action.  This entire art is reduced to four quantities: Course, Distance, Latitude, and Longitude, which mariners call the terms of navigation. [pp. 1-2]

 

Sección I: De la Aluja de marear, y del Rumbo q.e sique el Navío [Of the Ship’s Sailing and the Course it Follows] [pp. 2-5], while Sección II is De la Corredera, y Distancia que camina el Navío [Of the Track, and Distance that the Ship Travels] [p. 5-13]

 

Sección III: De las Cartas [Of Maps] [p. 13-30], is quite intriguing as it concerns the use of sea charts and maps of various kinds while at sea, including sub-sections, such as Of Planographic Maps; Of Spherical Maps or Reduced Maps; and About the World of Mapping with Spherical or Reduced Maps.

 

Sección IV: De la resolución de los problemas de Navegación por el por el cálculo; y ordenación del día rio p.a llevar la cuenta de la derrota del Navío [On the resolution of navigation problems by calculation…] [p. 30-55], features the sub-sections Establishing the ship’s position by two bearings taken from two points; By two bearings taken from a single point; By bearing and latitude diversion, or bearing and estimated distance; How to keep the point; and On the error resulting from combining the courses.

 

Sección V: De los casos en que debe hacerse correcciones del Corrientes [Cases in which corrections should be made to the Current] [p. 55-63], discusses matters, such as

Comparing the Estimate with the Landfall.

 

Sección VI: Del Octante y observaciones que se hacen con él [Of the Octant and observations made with it] [pp. 63 -], has the sub-sections On Geometry; On the graduation of the Octant; On the rectification of the aforementioned instrument and practicing observations with it; On the corrections that must be made in the altitudes of the stars; On the use of declination tables; Curious and exhaustive methods to determine the declination of the Sun…;  Elementary notions on the way of observing Longitude by Lunar distances; Arrangement of Clocks; Calculation of Longitude by Clock; and On some curious problems applied to Navigation.  This is followed by 14 ‘Problems’ or practical examples of calculations regarding the featured topics.

 

The text continues with Método de resolver los triángulos de la Navegación por vía de Aritmética [Method of solving navigation triangles by means of arithmetic], with 3 practical examples.  Next, is Siguen los Probelmas curiosos de la Navegación resueltos por trigometria y Asimétrica [Curious problems of navigation solved by trigonometry and asymmetry], featuring 12 practical examples.

 

There then follows a grand suite of full-page statistical charts of the Declination of the Sun (anchored to the meridian of the island of El Hierro, and not Cadiz as was the case with Juan’s charts) and the Amplitude of the Stars, updated to contemporary times, where appropriate, along with practical examples of how to use this data (ex. Finding the True Place of the Sun).  There is also a double-page chart, Uso de las tabula siguientes de ascensión recta el Sol en un egemplo [Use of the following tables of right ascension of the Sun in an example].

 

The work concludes with three folding leaves featuring diagrams corresponding to 24 points referenced in the text, including geometric diagrams, a sample map and a compass rose.

 

References: N/A – Manuscript seemingly not recorded.