Gold lettering + cm scale in well of stock - INCHES to METER printed conversion scale on back

special tables on back

Nomogram on slide and scales in well of stock

Co-branded (box & rule) with KLAWUN + 1st F-C specialist rule for Merchants - extra wide body

Popular desktop model + table on constants & 2 cursor windows in back ​

Cursor not shown in image - conversion table on back

No blind date stamp - coversion tables & factors on a plastic book-mark

6 slide tension adjustment screws in bottom edge + table of conversion factors on back with 2 cursor windows

3-digit model no. suffix was added as the 3/xx series transitioned into the 4/xx series + 6 slide tension adjustment screws in bottom side edge + table of conversion factors on back with 2 cursor windows

V & W scales in well of stock

Part of unusual limited series made from high pressure laminated (HPL) wood with metal inserts - patent no. DE892693

Special commission for Georg Heine, Stuttgart + front disc doubles as erasable notepad

Special commission for German organ builder Laukhuff (still operating) for scaling organ pipes (wood/metal flues & reeds) based on copyrighted design by German Richard Rensch (1923-1997) but preceded by German Wolfgang Adelung’s earlier (simpler) version - extremely complicated to use (cursor extension + graph paper needed for interim calculations) - superb quality but only 500 ever made - Orgelbau-Verlag started selling their own (inferior) version in 1986

See also smaller sibling - conversion table of fractions also on back 

N = Normaal (normal) + personally enhanced (lighter plastic outer baseplate & peripheral cursor hairlines) model of last ALRO Technical Director Han Wanders - see also smaller sibling 

Slide chart made for & © designed by KK/TRD consisting of consisting of 4 rings of energy saving tips ranked by low/medium/high investment levels for: (i)  heating systems (front) or (ii) lighting, energy & sanitation (back) 

Highly complex specialised layout of scales designed by Dr. A. Lips + facilitates 26 medical based calculations (metabolic-related on front & blood ph/gasses on  back) - read more … or try out  Andries de Man's two online simulations: (i) front & (ii) back 

Desktop version of smaller GoA with high-precision goniometric layout (double length Trig scales) by van Roon + specially commissioned flight computer for Dutch airline KLM for calculating course & wind correction 

Slide chart made for Dutch electronic multinational Philips with © design for their P300 bookkeeping minicomputer showing available functions according memory sectors A to S

Slide chart designed as planisphere by Dutchman R. Walrecht to calculate star positions & star signs at latitude 52º North & longitude 5º East for given date & time + just 1000 made but later versions made by PlantijnCasparie 

​Slide chart converting viscosity values between various standardised units + SYRES = Dutch company (still operating) specialising in commercial coatings & resins for buildings, boats, cars, etc 

Extra wide ​- 25cm (no. 0968) & 12.5cm (no. 868) versions also made

Extra wide ​- Multilog v/s Studio = extra LL00 & LL0 scales - 25cm (no. 0970) & 12.5cm (no. 870) versions also made

Series of imperial to metric conversion gauge marks on lower front face - s-d-£ scale is folded - inch scale on back - 25cm (no. 955) & 12.5cm (no. 845) versions also made ​

Co-branded D&P name in well of stock - ​inch scale on back

​inch scale on back

Co-branded D&P name in well of stock​

No slide - specially commissioned by Finnish stationers Ab Herman Lindell Oy - for measuring distances/areas - cursor extension suggests results were transposed for further working - name Herman Lindell + “import” & “copyrighted” in Finnish on the back

Modern day mit Strichteilung version (inner scales calibrated in more military favoured 6400 milliradians or MILS) of High Altitude Calculator for German Armed forces (NATO NSN No.: 6660-12-140-6737) for global missile trajectories or possibly jet stream & its effect on missiles or planes flying at high altitude

Slide chart made for the Eise Eisinga Planetarium (oldest still working planetarium) to calculate star positions & star signs for given date & time as seen from The Netherlands  

Missing chrome turning knob - based on drum-based design patented in 1894 (US513172) & tradition of drum-type Swiss makers  

No batch number but 4 tensioning pins & 4 chiselled out recesses in each end of top & bottom side edges to combat Bakelite shrinking problems + plain Bakelite back - read more ...

Stamped CASELLA but possibly made by UK maker W.H. Harling - upside-down scales on the slide probably a design feature when inverting the slide - read more ...

Slide chart (still sold) designed to assist artists in mixing watercolours & to achieve colour harmonies

Slide chart to calculate star positions & star signs for given date & time + designed to be read at night

Instruments for German armed forces during WWII used codes to hide maker’s identity - gwr​ = D&P + besides solving normal artillery-related distance problems, this naval version also takes into account drift of a moving vessel

IV = model with 4 adjustment screws in bottom edge - railway track scales - cm scale in well of stock​

QR = “Quadrat-Rechenschieber” - commissioned by “Gebr. Wichmann” (stamp in well) - probably classroom training aid for anti-aircraft gunners - layout consists of two pairs (upper set 0 - 50 & lower set 0 - 15.8) of non-logarithmic independent root scales (no interaction) derived from a set of tables by German Peter Timpenfeld & first published in 1888​ - non-conventional use of a cursor purely for positional summing of the squared values

Going by style of π gauge mark probably made by D&P + Maniphase = Dietzgen​ name for an Enhanced Mannheim + slightly longer slide + 6 adjustment screws & conversion table on back

Affectionately known as a “circular Gunter” - OEM version made by Gilson with novel clutch design & two cursors meaning a single D scale (effective length: 1067 cm) was sufficient + Trig scales + fraction/decimal conversion scale on back act as lookup “tables” 

Rare duplex Coggeshall with 4–40 GIRT LINE for volumes of round timber + 2 sets of brass gauge pins (marked 0,16, 8 & 8,16, 0 respectfully) for round, 8 or 16 sided timber + INVERTED LINE (AI scale) for volumes of rectangular timber - compared to Langley version layout front & back reversed

Seg Ly. scale on front face is for gauging when the cask is lying on its side + SPH’D scale on back face is for calculating the spheroid

Serial no. = 36 - called Apparatus for the Observation of Fire was intended for use by lance-corporals & corporals in the field & not on a desk - issued by Min. of Defence (inventory no. 302SB) ​

Post 1824 because of IM B & IM G gauge marks signify change from Winchester to Imperial based measurement - bottom Seg Ly. scale is for gauging when the cask is lying on its side

Little known French maker (Drancy, Paris) - plastic models similar to Graphoplex - unusual wide body + top LL scale not standard for a Rietz making the layout somewhat unconventional

Trade rule calculating over/under proof alcohol, gauging, blending, stocktaking, discount & profit + later Gloucester Terrace address = possibly made by Lucas

OEM by Nestler - cm scale in well of stock + hand-written list of formulas on back

Robust military grade OEM for J. H. Weil & Co. - Trig scales are in Mils (6400 mils = 360 degrees)​

Two closed windows with cursor line in back + see also pocket 643 sibling

​Late model as colours have sweated or bleed because cheaper methyl ethyl replaced phenol as etching agent - two closed windows with cursor line in back

Name of NL company Ingersoll-Rand in well of stock - one open window right with 1 hairline in back = see also desktop 6245 sibling

DYNSTAT is a mechanical impact/resilience testing method popular in Germany (DIN 53435) for testing small samples of plastic ​

Desktop version of 25cm model 255 - ​§ scales on front face for converting degrees into radians & vice-versa - supposedly for Advanced Electrical Engineers.

metal end braces - desktop version of 259​

Branded in well but no discernable model no. + table of conversion factors on back - also sold as Tamaya 4480 

Meteorological Office (MO) No. 676/38 - innovatively two slides can be locked together & act as one or when unlocked, move independently BUT even when unlocked, if top slide is moved it takes bottom one with it.

Serial no. = 48 - called Apparatus for the Observation of Fire was intended for use by lance-corporals & corporals in the field & not on a desk - issued by Min. of Defence

15” version of Autocrat model with extension of cm scale (16-32) in well of stock. “British Made” - steel back + paper table of conversion factors

Unmarked - cm scale extension + 6 slits in well of stock - L scale reversed

Serial no. 322 + 5 adjustment screws & conversion table on back

Serial no. 445698

Serial no. 902506

N prefix for new version + serial no. 740727 + 5 adjustment screws & conversion table on back

N prefix = new/modified version + serial no.: 235840​

N prefix for new version + serial no. 699855 + stripped back scale layout for just x, ÷ & proportions + 5 adjustment screws & conversion table on back​ + with the lid open can be used in box!

N prefix for new version + serial no. 106473 + 5 adjustment screws & conversion table on back

​Special anniversary gift from Ros - serial no. = 1685

Specially produced chunky model with a Mannheim-like layout based on Mils - read more ...

OEM version made by Faber-Castell - British pre-decimal + 6 slide tension adjustment screws in bottom side edge + pictorial instructions & tables of constants on back

On balance probably KHH-made (some but not all of typical KHH traits) but mysteriously “Sistema Rietz” (Spanish) in gold lettering on slipcase & stamped in well of stock - paper data slip missing from back​

Made in the style of earlier Russian Prometei-made military/pilot slide rules. Intriguingly the military RWTL-2 labelling (in German) on the box stands for Rockets and Weapons Storage - 2 @ Hennersdorfer Heide, Lower Austria. ​

ROCT (GOST) Russian State Standard No. = 5161-57 + conversion factors & formulas on back​

Serial No. 155202 (“15” correlates to scale length & “5202” = no.) + version “E” = Einfach/elementary

Serial No. 2237 (possibly correlates to overall scale length) + version “E” = Einfach/elementary

Serial No. 751030 (“75” correlates to scale length & “1030” = no.) + version “E” = Einfach/elementary

Serial No. 82 with sin, cos & tan scales calibrated in 6400 NATO Mils favoured by the military + sin & cos scales are divided into 4 subscales + see also smaller siblings

Model suffix “E” = Einfach/elementary - see also smaller sibling - try out here the online simulation created by Andries de Man

Serial No. 3474 + model suffix “E” = Einfach/elementary & “A” = additional scales for GBP & imperial/metric conversions - try out here the online simulation created by Andries de Man

​Serial No. 4100 + model suffix “R” = with reciprocal scale & “Z” = extra Zins/interest scale - see also smaller sibling

Model suffix “T” = Technisch/technical scales + more accurate later addition to product range marketed to both schools & commerce - see smaller sibling - try out here the online simulation created by Andries de Man

​Interesting & useable layout of scales

Use/purpose of the many gauge marks is unknown - SR built into desktop stand for Nederlandse Kabelfabriek (NKF - Dutch cable factory in Delft)

Possibly a basic model for other specially commissioned designs but use/purpose of the many gauge marks is unknown - SR built into desktop stand

​Commissioned by Coöperatieve Condensfabriek Friesland (CCF a Dutch dairy specialising in condensed milk) - for checking the waybills for shipping/tranporting goods   

serial no. = 3545 with knurled metal turning knob - stand allows drum to be locked vertically to save desktop space

​Both non-standard scales folded & apart from NESTLER name in well no other markings

tables of conversion factors on back

tables of conversion factors on back

Tables of conversion factors + 2 cursor windows in back - long scales (folded @ Pi) & desktop model meant accuracy of 0.03% with smaller sibling 0270

Top non-standard scale is for rapid calculation of tension losses in copper wires + bottom non-standard scale is for calculating peripheral velocities (D scale displaced by pi/6 or 0.5326) - table of conversion factors & 2 cursor windows in back​ + smaller sibling 0370

cm scale in well of stock + tables of conversion factors on back

cm scale in well of stock + table of conversion factors on back

Unusual scale length​ - tables of conversion factors on back

cm scale in well of stock + tables of conversion factors on back - ex Shell (B.P.M.)

Not demonstration type but 10f only 4 engine-divided (only maker capable of desktops >50cm) + early production year from 1908-1911 style of company name - read more ....​

cm scale in well of stock + tables of conversion factors on back

Not demonstration type but 1 of only 4 engine-divided 100cm models (only maker capable of engine dividing desktops >50cm)​

cm scale in well of stock+ tables of conversion factors on back - long scales (folded @ Pi) & desktop model meant accuracy of 0.03% + has smaller & later sibling model 0270

Tables of conversion factors on back - model later replaced by 0286 Geometer + see smaller sibling

German silver screws + cm scale in well of stock + Table of constants on back

Unusual scale layout + British pound sterling (£ s d) scales on back of slide + conversion tables on back

Largest of only 3 cylinder/drum models

Modern day 360 degree Winkel in Grad version of High Altitude Calculator for German Armed forces (NATO NSN No.: 6660-12-127-6307) for global missile trajectories or possibly jet stream & its effect on missiles or planes flying at high altitude + read more ...

Slide chart copyrighted design & trademarked DIAL-A-CHORD name

Slide chart designed as planisphere by Dutchman R. Walrecht to calculate star positions in Northern Hemisphere for given date & time but in a special eclipse of the sun (11/08/1999) edition showing positions of sun, moon, planets & perseids meteor storm + based on version made by ALRO

One of earliest weight calculators for rectangular & square section bars from little known UK (Newcastle on Tyne) instrument maker/optician 

After preloading 11 of 25 removeable slides the chosen scale layout can "simply" calculate overall amplitude ratio & phase of a multiterm transfer function

Invented & patented (GB189313940 - 1894) by Charles Gooch as an impoved gauge for centering & mounting photographic prints et al - the 2nd slide is attached on top of the slide in the stock by means of a metal sleeve/clamp ​

Patented (GB187801044 & US219246) design by George M. Fuller - serial No. 4869 with conversion tables, natural sines & Birmingham Wire Gauge on inner fixed cylinder

Meteorological Office (MO) No. 1979/43 - possibly made for Stanley by J.J. Hicks or A.G. Thornton - adoption of standard rates of ascent removed need for Mark I poly-slide (2) but 4th cursor needed for “tail method”

A 48th Wedding Anniversary present from Ros - patented (GB187801044 & US219246) design by George M. Fuller - hand-held early shorter version with no spigot & no serial no. + conversion tables, natural sines & Birmingham Wire Gauge on inner fixed cylinder

Unusual fixed cursor extending the range of a relatively short scale length - read more ...

​Narrow body design by E.A. Aisenstadt & date stamped in back

Unbranded but attributable to Thornton (horizontal/flat diamond box identification marks & reversed bottom edge scale) - traditional B scale replaced by upward pointing arrow - read more ...

Rietz type without Trig scales but with extra Thornton patented differential Trig scales - conversion tables on back - “big brother” version of PIC 111

Extra Thornton patented differential Trig scales - conversion tables on back - "big brother" version of PIC 121

Extra Thornton mini Y & Z scales for financial calculations + patented differential Trig scales + Vector analysis scale - V & W scales in well of stock (plastic well cursor) - conversion tables on back - “big brother” version of PIC 131

V & W scales in well of stock - conversion tables on back of stock

conversion tables on back

Decimal/10-bit binary (base/2/base 10) rule. Serial no. 019 blind-stamped in back

Uncannily similar (visual & construction) to much earlier Swiss-made Lightning Calculator (Blitzrechner) of Ernst Billeter - extra % scale for discount &/or profit margin mark-up calculations - son of K. Emil Tröger who took over the company his father founded

Standard values of AG Pathophysiologie d. Atmung - “1” in equilateral triangle = East German (DDR) post 1950 certification mark for “1st or good quality” - Karl Emil founded the company later taken over by son Hans - 8 mini specialist scales overlaid on D scale

Unmarked but obviously Karl Emil made - Neues Deutschland = East German daily newspaper - Cicero is a typographic unit of measure similar to a pica but with 15th century origins

“1” in equilateral triangle = East German (DDR) post 1950 certification mark for “1st or good quality” - Karl Emil founded the company later taken over by son Hans

Extra wide (3¼") ​body with mysterious non-standard  folded long-scales + 3 extra § scales in well & table of possible constants on back

Slide chart to calculate star positions & star signs but apart from being German & having 1410 as a possible model number on the back, its provenance is a bit of an enigma

Robert Noel-Bentley design (patent CA489176 - 1952) for calculating (pre-shipment) physical characteristics of commercially manufactured large & heavy rolls of paper - possibly made by Blundell.

Invented by Edmund Gunter (1581-1626) - standard layout for a Gunter i.e. ​Diagonal scale on front face + full-length scales on back

Wide-bodied & well made but otherwise no clues as to the maker​ - scale layout identical to Robson model

Wide-bodied model possibly made by BH ​

Made for specialist German music publisher Orgelbau-Fachverlag for scaling organ pipes (wood metal flues & reeds) but a follow-on cheaper & thinner version of original limited high-quality Laukhuff Orgelpfeifen model by F-C + Table of frequencies on back

Slide chart A-N Type 1 for aeronautical use based on an original design by Gilbert T. Rude but later modified by Elmer Collins + set consists of a double-sided white base plate (side for each hemisphere) & 6 transparent plastic overlays  

Invented by Edmund Gunter (1581-1626) - replica made by KRING member Ton van Oosterhout ​- standard layout for a Gunter i.e. ​Diagonal scale on front face + full-length scales on back

No makers name or logo - catalogued by Colin Barnes as “Lloyds Register Slide Rule” - table of constants on back

Rare duplex Coggeshall with 4–40 GIRT LINE for volumes of round timber + 2 sets of brass gauge pins (marked 0,16, 8 & 8,16, 0 respectfully) for round, 8 or 16 sided timber + INVERTED LINE (AI scale) for volumes of rectangular timber - compared to Dring & Fage version layout front & back reversed