A Della Torre, London, telescope

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Lovely name, Della Torre, but how come someone with an Italian sounding name was in London making telescopes in the early 1800s? Anthony Della Torre was working as an Optician in London from 1805 to 1823: he was sometimes known as ‘de la Torre’. He was located at 12 Leigh Street, in Red Lion Square, from 1805-11, and 4 Leigh Street, Red Lion Square, from 1815-23. There’s not a lot known, indeed Leigh Street has disappeared, but if the houses were actually the ones now on Red Lion Square, they were expensive addresses. However not quite in the Strand/High Holborn normal area for telescope makers and traders.

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Italian immigrants to London over the last thousand years are discussed on www.italophiles.com, which points out that they were concentrated in the early 1800s in this northern part of London. Amongst their number were various instrument makers – such as Negretti, eventually founding Negretti and Zambra; and Martinelli, who made barometers. There are still many people of this name in the UK, and the USA.

The Telescope

dscn4347So the telescope dates from the very first 20 years of the 1800s: it is engraved on the first draw, “Della Torre & Co, London”. It is an elegant, narrow bodied, two draw telescope, with a mahogany barrel and lens protectors at each end. The screws that are present mostly  look original: one on the objective carrier does look like a replacement. The telescope gives a nice image with an easy focus.

The objective is again a triple lens combination, but compared to the Lincoln this time the Crown glass convex lenses that sandwich the flint glass concave lens (the central lens on the pic with the slight pinkish tint) are very clear of colour, with only the slightest green tint. All are held in place with a screw in ring, much easier to deal with than a peened structure. The objective is small in diameter, with only 18mm of visible glass, within the total telescope OD of 37mm: this is reminiscent of much older Italian (and Dollond C18th) designs. The lens carrier incorporates a sideways sliding cover to protect the objective. As you see, all the screw-threads work well.

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Overall length is 49cm (19.4″) extended, and 21.4cm (8.4″) when closed. The eyepiece lenses are in two standard cartridges, but the final connection to the viewing eyepiece cap is novel, in that the shoulder is not part of the cap, it is attached to the first draw permanently.

Conclusion

Altogether a pleasing 200 year old telescope. It was acquisition #167 in 2012. Value now? Difficult to say, as there are very few about, and I’ve never seen another for sale. After listing this here, and receiving some enquiries, I have decided it should be sold, and the price listed on Fleaglass.com is £300.

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A Lincoln, with a triplet for the objective

This is a medium sized telescope, a three draw with a mahogany barrel, made by Lincoln, which is typically in the late 1700s. It was probably built for a Cavalry officer, or for a country gentleman’s use. It is 7.75” (19.7cm) closed, and 22.5” (57cm) long when fully open. Outer diameter is 1.625” (43mm). Performing fairly poorly, and with lenses rattling, when it was delivered to me in 2014, the operation of the scope was much improved by getting everything back into the right place!

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The Lincoln name

The name engraved on the first draw of this telescope is quite simple: it just says Lincoln, London, with the first word in script, like a logo: and the latter word is written as “London” is typed here. So there is very little to go on to help date it. However it uses a triple lens as the objective, which would have been one of the ways to avoid infringing the Dollond Patent, which maybe lasted from 1762 through to around 1785, although he did petition to extend the life of the patent….. I must check that out. A similar triple lens would not have been used before 1762, so it was not made by Thomas Lincoln, who was active from 1720-1762, but by his son, Charles Lincoln, who operated 1765-1805.

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The picture above shows the name engraved on the first draw, but it is significant that it is what I would describe as on the ‘right hand side’ of the telescope. This means the first letters of the lines, the “L” of Lincoln and London, are closest to the eyepiece. This is the old fashioned style, dating from early C18th up to about 1790. After that, the fashion changed, and the end of the word was closest to the eyepiece. However, it is always possible that Lincoln clung onto this approach, and continued writing his name the way he always had done! So it is generally an indicator of earlier than 1790, but this varies from maker to maker.

The three draw design, which requires three separate different sized tubes, was probably not possible before 1760 either. It is a design that maybe appeared in the 1770s-1780s. After Thomas Lincoln died, in 1762, his son Charles took over the business, and is recorded as an Optical Instrument Maker operating from 1765 to 1805. This telescope could be from anywhere within the 1780-1805 period.

Charles Lincoln operated from Leadenhall Street in London, a popular area for optical instrument makers. From 1772 onwards he was at 62 Leadenhall Street, with an address starting with “Sir Isaac Newton’s Head” – presumably this was the sign over the door. One of his apprentices was a William Cox, who later traded in London, but this Cox was not related to the Plymouth/Devonport-based William Charles Cox.

Telescope design

As mentioned above, the triple objective lens is distinctive, as it is made from two crown glass convex lenses (with a greenish tint) and one concave flint glass lens (clear of colour). These lenses are not well held within the brass ring at the end of the barrel: it appears that the ‘as made’ state was that these were held in place when the rear edge of the mount was peened over the rear lens, but at some time, maybe to clean between the lenses, this slight peening has been pulled back.

The eyepiece design is fairly standard. The last draw at the eyepiece contains two separate cartridges, one at each end, with two lenses in each. The lenses appear to be original, solidly mounted in their brass carriers that are threaded into the cartridges, but this section, which acts as a microscope, seemed initially to offer a very narrow field of view. This was then apparent when using the fully assembled telescope, when again the field of view was very narrow. The problem was identified as because of the positioning of the small orifice within the bottom cartridge. Somehow this had been loaded with the lenses in the wrong ends, and with the orifice positioned further away from the objective lens, the problem disappeared, but left a “jagged edge” appearance around the visible image disc. This was also eliminated, giving a much cleaner image, when the other cartridge closer to the eye was rotated and the lenses then replaced, although this orifice appears to be much larger and closer to the centre between these other two lenses.

dscn4338The mahogany barrel is fine, and has been improved by re-polishing; the connecting shoulders at the end of each draw are standard, with knurled end flanges. The screws holding the brass part of the telescope to the rear end of the barrel are not original; at the other end they are the originals: this brass mount is therefore slightly loose!

The objective lens has a push-on end cap present, the fairly standard design eyepiece cap has a flat end-face and includes an internal flip-across cover to protect the lens.

Acquisition #197

1860 Presentation Dollond – For US Sale

A correspondent in the Milwaukee/Chicago area has an interesting Dollond telescope for sale, which dates from at least 1860. This is a classic single draw, large “Day or Night” naval unit, measuring 39” open, and 21” closed, with a sliding lens cover on the eyepiece. The sunshade is still present on the objective end.

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Presentation Engraving

The draw is engraved with the normal “Dollond London” and “Day or Night”, but also has an elaborate explanation as to why it was presented to Captain G.V. Argles. This reads:

Presented

to

Captain G V Argles

of I G S N Co’s steamer “Agra”

for services rendered to the

Ganges Co steamer MIRZAPORE

while aground in the Chokah Channel off Kaunsul

October 1860

Singh McCardy

Manager

Ganges S N Co Ltd

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This is a fairly typical reason for a presentation to a ship’s Captain, from another ship that was either foundering or in difficulties, when he offered and provided assistance. The exact place is difficult to locate now, as the area is no longer part of India, but is in Bangladesh, and many town and place names in India have been changed or the spelling adjusted.

20160925_205931It has been possible to determine that “IGSN” is the India General Steam Navigation Company (established 1844), and similarly “Ganges SN Co” is probably the Ganges Steam Navigation Company. References also show that there were many steam boats travelling up the Ganges, typically from Calcutta (now Kolkata) to Benares (now known as Varanasi, 600km NW of Calcutta in Northern India): these boats would need to stop to load more coal maybe three times during this journey. In 1849 there were 15 privately owned steamers travelling this route, three of which were 1000 ton P&O liners. The Indian Government, who supplied the coal to the intermediate coaling points, itself used ten riverboats. In fact one of the coaling stops was at a location/town called ‘Mirzapur’, close to Benares.

20160925_202125The only reference found relating to ‘Chokah’, was for the town of Choka, near Patna, on this route up the Ganges (238 miles from Calcutta), where the channel was said only to be passable by steam boats from July to October. So this could have been where the Mirzapore steamer came to grief: it is significant that the date on the telescope is for October that year!

Enquiries, please, via this website.

Photos of the telescope

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A Ramsden 8-draw telescope

This is a telescope referred to me by a correspondent in Vienna, Austria, to whom it was given as a birthday present from a friend. The background history was that it belonged to the friend’s Grandfather, but it had not been used for at least 50 years.

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The Grandfather had travelled frequently from London, where he lived, to South Africa, where he had had a business in Pretoria. This takes the ownership back to maybe the late 1800s, 1880-1900, so not quite as far back as when the telescope was made. After cleaning for 5 hours, using Brasso equivalent on the brass, and cream on the leather covering, this beautiful telescope emerged, with the name Ramsden, London, engraved on the first draw.

Quite reasonably the question arose as to whether this was indeed from Ramsden, who died in 1800, so he asked for a review of the design to see if it was genuine. Some of the extensive photos supplied of the unit are shown here.

Ramsden and small telescopes

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Ramsden made 3-draw telescopes, and even one example of a 4-draw was presented on EBay recently. If this 8-draw multi-draw scope is genuinely a Ramsden it will be one of the earliest multi-draws produced. For a Dollond or any other maker from that time, it would be difficult to prove that it pre-dates 1800, as many of them continued trading using the same names well into the 1800s. The question is as to whether there was the capability available in the brass tube industry to draw tubes of the many diameters needed to make such a unit, back in the 1790s.

img_2244The second question would be as to whether there might be a demand – nowadays we would say a market – for such a design, when many of the scopes were used on-board ships. There, on board, there was plenty of space, and the small (pocket?) size (when collapsed) would not be needed. Ramsden, and Berge who followed him, also served the market for the country gentleman, who wanted a smaller, easy to carry telescope: see the “Gentleman’s silver telescope” on this website, and the Ramsden 3-draw units. There was also a market with cavalry officers, who needed units they could easily either carry in a small leather tube, or pack onto a horse. Watkins produced such scopes, as we see in the story about Captain Gerrard on this site, who used it later in the C19th, or also see the Bianchi 3-draw scope used by Lt Rolfe in the Peninsular War (1807). So it seems the demand would have been there.

This Design

img_2251The details of the design are just what would be expected from Ramsden, and are very high quality: I would say beautiful but that would make it subjective. The connectors between the draws are built with the threads recessed into the receiving draw by around an inch, and with a shoulder under the end of the receiving draw tube, to increase/improve the rigidity of the optical axis of the scope. The thread length used is also longer than average.  This approach is also used on the examples of multi-draw telescopes produced (later) by Cary, Abraham, Cox and Carpenter, that I have in my own collection. It was not used on any of the 3 or 4-draw telescopes produced by Ramsden or Berge that I have seen.

img_2252The internal lens cartridges and lens mounts are well constructed, and all the threads on this example are easily unscrewed: even the objective lens pair and its mounting. It has an objective lens cap, for protection, but no sunshade: this is similar to the other designs of smaller scopes, and the multi-draws quoted above.

The Ramsden signature is on the first draw, with the letters starting at the objective end of the scope, which might indicate a later build date, around 1890-1900, as earlier the lettering might have been reversed (ie written on the other side of the draw): the Ramsden and Berge telescopes I have studied have the signature in the same orientation as this one, so are all presumed later models.

The knurling on the connectors – which can be used as hand-holds to extend the draws, but the wider diameter is also needed so that the draws are not pushed into the next larger tube – is very well defined, not showing any bashes or dings: indeed the whole scope is remarkably free from dings. In the photo the knurling looks quite sizeable, but remember this is a relatively small diameter scope.

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The photos above show the objective lens pair and mount components.

The barrel is brass, covered with black leather. When closed the telescope is only 15cms long (approx. 6”), but once fully opened the total length is 73cms (nearly 29”), giving a high magnification capability. The quality of the image, and the magnification, is quoted as very good.

The Hiccup on the 4th draw?

ring_adjMy colleague who has this telescope considers the 4th draw to be different in construction, but I regret I can’t understand what function the difference might have, or whether it is real. There is a separate photo of this draw, it is possibly a shorter length, reduced by 12-15mm at least, with a separate (mounting?) ring on the end of the connector. It might be that this element (draw) had a problem in production, and the extra ring was needed to ensure the correct mounting position/alignment of the tubes? Or did it just reduce the full extended length to make the focus easier to locate?

Questions or Comments?

If you have any comments that might help our study of this telescope these would be welcomed. It is suggested that this is one of the first and earliest brass 8-draw or multi-draw designs of telescope, produced by Ramsden in the late 1790s!

Subsequent correspondence has been fairly sceptical, from the point of view of the multi-draw design and tube availability not dating back to the 1790s. However one significant feature that I missed is the shaping of the eyepiece. This triangular style is not a shape that was used in the 1790s, when they were flat sided, or bell shaped. One comment was that this was more likely to be a French in design, from the late 1800s.

I would think the only further test (so far not possible) would be to check the optical quality of the scope, to see whether this aspect aspires to the normal high standard from Ramsden.