# NavList:

## A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding

Message:αβγ
Message:abc
 Add Images & Files Posting Code: Name: Email:
Re: Showing a Mercator Projection is not a perspective projection
From: Robin Stuart
Date: 2016 Dec 31, 12:43 -0800

The relevant text can be found here.

Probably the key phrase is "this sphaerical superficies iIncreasing successively from the Aequino∣ctial towards either pole, until it come to be of aequal diameter with the cylinder". I'll leave to you to decide whether this description is consistent with my interpretation.

Let this Sphaerical superficies swel like a bladder, (whiles it is in blowing) aequally alwayes in every part thereof (that is, as much in longitude as in latitude) till it apply, and joyn it self (round about, and all alongst also towards either pole) unto the concave superficies of the cylinder: each parallel upon this sphaerical superficies increasing successively from the Aequino∣ctial towards either pole, until it come to be of aequal diameter with the cylinder, and consequently the Meridians still wide∣ning themselves, till they come to be so far distant every where each from other as they are at the Aequinoctial. Thus it may most easily bee understood, how a sphaerical superficies may (by extension) be made a cylindrical, and consequently a plain Parallelogram superficies; because the superficies of a cylinder is nothing else but a plain parallelogram wound about two equal equidistant circles that have one common axtree perpen∣dicular upon the centers of them both, and the peripheries of each of them equal to the length of the parallelogram as the distance betwixt those circles, or height of the cylinder is equal to the breadth thereof. So as the nauticall planisphaere may be defined to be nothing else but a parallellogram made of the sphaerical superficies of an Hydrographical Globe inscribed into a concave cylinder, both their axes concurring in one; and the sphaerical superficies swelling in every part equally in longitude and latitude, till every one of the Parallels thereupon be in∣scribed into the cylinder (each parallel growing as great as the Aequinoctial:) or till the whole sphaerical superficies, touch and apply it selfe every where to the concavity of the cylinder.

Certain errors in navigation detected and corrected by Edw. Wright ; with many additions that were not in the former editions.

Browse Files

Drop Files

### Join NavList

 Name: (please, no nicknames or handles) Email:
 Do you want to receive all group messages by email? Yes No
You can also join by posting. Your first on-topic post automatically makes you a member.

### Posting Code

Enter the email address associated with your NavList messages. Your posting code will be emailed to you immediately.
 Email:

### Email Settings

 Posting Code:

### Custom Index

 Subject: Author: Start date: (yyyymm dd) End date: (yyyymm dd)