Casartelli of Manchester map reading pocket magnifying glasses

[Sam Gerrits]

Dear experts,

I came across these wonderful map-reading magnifying glasses by Casartelli of Manchester. They were used as thread counters, before the war around 1908.

How common would these have been in the trenches of WW1? Would they only have been issued to officers, to all soldiers? Or only to map reading specialists?

Thank you!

Sam Gerrits

http://www.deactivated-guns.co.uk/militaria/wwi-british-map-reader-pocket-magnifying-glass-issued-to-c-haslam/prod_8478.html

https://www.worthpoint.com/worthopedia/vintage-casartelli-manchester-map-276371819

 

 

[WhiteStarLine]

Hi Sam and welcome to the forum.  What an interesting first post!

Personally, I'm not wedded to the idea that these were map readers, or practical in the field or issued to soldiers. I can see how they would be perfect for precision examination / measurement of textile samples and for microphotographs, popular in the 1850s and 60s.  However, these items are small and could be pushed into place against the convenient backing piece and examined in detail and in the case of textiles, thread counts obtained using the supplied ruler.

Over 23 million maps were supplied and as a generalisation they covered 8km x 5km at the 1:10,000 scale.  So no chance of folding the map into small sections up and pushing it against the back of the Casartelli linen proofer.  I can see that you could extend it to become a conventional magnifying glass, but you would then just buy one of these instead of a precision instrument designed for another purpose. 

Anyone doing specialist artillery work had a plotting board, protractor and device for squaring off coordinates similar to a modern roamer.  The linen proofer would not have assisted with the latter.  A surveyor or officer interpreting aerial photos would have needed a large table magnifier or good handheld magnifying glass to resolve the incredible detail in a photo.  This kind of detail simply did not exist in large scale maps used by infantry or artillery.

Quote

 

Working in less than ideal field conditions, often in poor lighting and relying on handheld magnifying glasses, analysts looked for changes in the landscape, such as the appearance of new trenches and foot or tire prints that would indicate the presence of enemy forces,  Maps of The First World War: An Illustrated Essay and List of Select Maps in The Library of Congress. Ryan J. Moore

 

So to finish up with some random observations:

• Casartelli instruments were highly regarded and appear frequently in auction sites.  If widely used by the military, I would expect to see many photos with the familiar broad arrow stamped on them.
• If they were widely used, even by private purchase, I would expect the word casartelli to appear often on this long-running and diverse forum.  It only appears one other time, to discuss a telescopic sight on a 60 pounder artillery piece.  That post was from 2004. 
• I cannot find evidence that they were purchased by the military, let alone issued to officers or to soldiers.  While specialist surveyors and cartographers did map production, map reading was a generalist skill.
• The militaria site you quoted assumed C. Haslam would have most likley [sic] been a serving officer in the British army.  Also without evidence they also say: This devise [sic] was used on the battlefield during WWI.  The only other claim to that effect seems to be an Australian RSL that uses almost the exact phrase in its catalogue.

I hope you stay and enjoy the forum.  None of us take ourselves too seriously, so if you or anyone else discover evidence that contradicts all the points I've made, then all of us interested in Western Front mapping would be truly interested to have discovered another technique.  Survey and map production progressed from a handful of maps of French & Belgian forts in 1914 to an entire country re-surveyed on the ground, with theodolites, aerial photography, teams of surveyors and accurate contour measurement.  Some surveyors even lost their lives surveying trenches. 

Cheers, Bill

 

[Sam Gerrits]

Hi Bill,

Thank you for your most generous welcome and your comprehensive reply to my question. I see you are interested in Australian stuff. I have some material on the influence of Dutch geologist Dutch Henk Stheeman on the invasion of Borneo by the Australian troops, that suffered heavy losses in WW2. I know, wrong war, but maybe of interest to you.  

What you say about the Casartelli thread counters makes a lot of sense. I am really happy with your quote:

"Working in less than ideal field conditions, often in poor lighting and relying on handheld magnifying glasses, analysts looked for changes in the landscape, such as the appearance of new trenches and foot or tire prints that would indicate the presence of enemy forces."  Maps of The First World War: An Illustrated Essay and List of Select Maps in The Library of Congress. Ryan J. Moore.

I was looking for evidence that the British WW1 troops, specifically the ones that participated in the Battle of the Somme,  had access to magnifying glasses. Because I'm trying to find out how much they would have seen of their little tormentors, the body lice. 

Cheers,

Sam 

 

 

[WhiteStarLine]

Sam, I'm no expert on this but I doubt most soldiers had the money to purchase or the room to store or a safe way of carrying relatively fragile magnifying glasses.

From my limited knowledge, if they were in billets they used hot irons and if they were in dugouts they used matches or candles, mainly trying to get the lines of lice (concentrations) rather than individual lice.

In my grandfather's hut in England while still training, someone put some lice into his singlet to spook the inspecting officer:

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one dirty bunter put two in his singlet just before inspection - he used to have a look every 5 minutes to see poor Chat had not escaped..

[Sam Gerrits]

Haha, thank you for this anecdote. Got a good chuckle out of that one.

And thanks for the practical insight into how they got rid of the lice. Interesting stuff. 

Found the seminal article on trench fever in the BMJ by McNee et al. from February 12, 1916, it states:

It's absence (of rheumatic fever) has been one of the most striking things in the campaign, and effectually disposes of any connexion between this fever and wet or cold. These undetermined fevers have from the first been the hunting ground of the bacteriologists, who with their laboratories are disposed in a line along the front, together with a few in special places further back. The bases have, of course, their own bacteriologists, and are not now under consideration.

So there were many guys with microscopes near the front line. Did not expect that. 

If you find anything else on magnifying glasses, I'd be very much obliged. :-)

Best!

Sam