Magnifiers: a closer look (XVIII)
The beginnings of optical magnifying

One might assume that a quick glance into the Wikipedia should clarify whether magnifiers were invented in antique (Roman, Greek) times or much later, in the 13th century. Funny enough there is a strong rift between those two versions. We are going to illustrate those two opinions in shorthand manner, for your entertainment and astonishment:

(1) A bestseller author named Robert Temple claims in his comprehensive monograph "The Crystal Sun" [Temple 1999], in particular on the basis of the so-called Nimrud lens (fig. 1) that lenses were in use as magnifiers and craft tools already in antique times. In order to enhance his view of the scenario we might add that the antique Roman empire, a political and military heavyweight, should have been perfectly able to invent and use such simple things as hand magnifiers!

Fig. 1: The so-called Nimrud-Linse in the British Museum. It was found in an ancient city called Nimrud (today in Iraq), excavated by Austen Henry Layard in 1850.
Image source: user:geni License: CC-BY-SA.

(2) The scholarly opinion, pointed out e.g. by Wolfgang Gloede [Gloede 1986] is delivering a contradictory account, based on practical craftmanship:

"Those who do not want to believe in what specalists in optics are thinking (about those antique "lenses") are advised to perform a practical check: simply go ahead and try to perform some fine work through such a quartz crystal lens! No chance!"
(The original text of this quotation is written in German language, rather sluggishly translated by us - still trying to grasp its essence)

Source: Richard Greef, 1921, quoted by [Gloede 1986]

It appears that even in much more modern times magnifiers were absent in workshow environments. Let's have a flashback look into a renaissance workshop (below), run by Étienne Delaune, a famous french goldsmith and engraver. The apparently older master is bearing spectacles which were quite usual at this time but there are no traces of classical magnifying devices whatsoever.

Fig, 2: Scenery in a goldsmith's workshop run by Étienne Delaune. Reproduction of a historical engraving stored in the Louvre collections, dating back to 1576.
Image source [Lacroix 1887].

Fig. 3: Detail of fig. 2. Though it appears that fine engraving work is performed in this scenario, the younger workers are apparently managing without any magnifying device. Only one of the men, presumedly the eldest is bearing spectacles. This type of spectacles, fixed to the head by strings ist typical for the period. Besides, those slim strings are not visible on this picture - but without them the master would have lost his spectacles!

When jumping to the 18th century folding magnifiers appear to have been abundant, probably used as a kind of bargain spectacles as well. We are going to show two examples of this type below:

Fig. 4: A very old folding magnifier, made of horn, with a rather low magnification, possibly used liked spectacles. Length of housing (closed) 9.5 cm, weight 38,1 g. The handle shells are markedly convex. Rivets made of iron. Colorless glass, but with hefty bubble inclusions, visible by means of the bare eye. The lens edges appear to be ground in a very rough manner. 5.7 diopters (a value which translates to a very weak, ca. 1.5x magnification).
According to William Poulet [Poulet 1986] magnifiers of this type can be dated back to the end of the 18th century: see Poulet, volume I, images Z327, Z348, Z361 and Z362.

Fig. 5: A further, very old oval folding magnifier, made of horn as well. Length of housing (when closed) 7.9 cm, weight 78.0 g. Again with markedly convex handle shells. Rivets in brass with central iron pins. The lens holder ring bears traces of a vivid dark green colour, probably original! The glass is colorless, with bubbles similar to the ones in the glass of the magnifier shown in fig. 4. We measured the 3.7 diopters (translating to an extremely low magnification of ca. 1.25).
Magnifiers of this type can be dated back to the 18th century [Poulet 1986]. See Poulet, volume I, images Z337, Z346 and Z354.

Abb. 6: detail - a rivet of the oval magnifier. Diameter ca. 5 mm.

Funny enough the air bubbles within those old lenses typically are not spherical but kind of oval, thus revealing a very dynamic production process:

Fig. 7: typical distorted bubbles in the lens of the instrument shown in fig. 5. The height of this bubble is ca. 0.2 mm - not visible with the bare eye.

The 18th century is marking a kind of type explosion in magnifier making, with myriads of product variations. It must be assumed that in this period a broad variety of professional uses was building up (in textile trade, engraving, jewelry assessment etc.).
In contrast highly specialized, stronger single lens magnifiers for purely scientific purposes are a completely different topic (see e.g. [Giordano 2006]) - some of those scientific instruments can date back to the 17th century and are extremely rare.

In the upcoming issue of the journal (in May) we will present and discuss an early model of a so-called "Nuremberg type" handle magnifier. The June issue will illustrate how ancient engravers might have enhanced their vision capabilities without the use of glass lenses!

Literature

It goes without saying that the literature choice below is quite arbitrary. Those books are primarily mentioned because we could make use of them in order to assess the production dates of some of our old hand magnifiers.

Paul Lacroix [Graveur]: Les Art et les Métiers au Moyen Age. Figure on page 227. Paris 1887.

Raymond V. Giordano: Singular Beauty. 2006.
[Annotation: this is a tiny but exquisite catalogue of simple magnifiers. Most of the book is devoted to luxurious magnifiers but some modest every-day instruments are included as well. Good bibliography].

Wolfgang Gloede: Vom Lesestein zum Elektronenmikroskop. S. 10-11. Berlin 1986. [Annotation: this books includes an excellent discussion thread culminating in the verdict that a wide-spread use of magnifiers in ancient times appears to be highly improbable].

William Poulet: Die Brille. Three voliumes with ca. 2.000 illustrations. Bonn 1978.
[Annotation: though this work is primarily covering the history of spectacles there is a wealth of illustrations showing magnifiers as well].

Robert Temple: The Crystal Sun. London 1999.

© Text, images and video clips by  Martin Mach  (webmaster@baertierchen.de).
The Water Bear web base is a licensed and revised version of the German language monthly magazine  Bärtierchen-Journal . Style and grammar amendments by native speakers are warmly welcomed.

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