Gunter Rule 12". Not a slide rule but it needs to live somewhere. A pair of dividers would be used to set the logarithm of one multiplier; by placing one point of the dividers on the second multiplier on the Gunter rule the answer would be read under the second point. 

This is a reprint of the scale from a Thacher Calculator. When using a scale like this as a Long Scale Gunter it is necessary to preserve the Distance and the Angle between 1 and the first Multiplier (2 in this case). The distance is preserved using Dividers and the Angle using a Set Square sliding along a Ruler. This is set up to Multiply 2.5 x 2. It is possible to use a Rolling Ruler to preserve the Angle but one needs to be extremely careful, therefore I prefer the Set Square. When set up on a Drawing Board one can slide the Set Square along the TSquare for greater ease. 

This is a reprint of a scale originally created by Robert Dawson, using Secant curves as its basis and similar to that used to create Whythe's Calculator. Multiplication of Complex Numbers can be achieved in the same way as Multiplication with the Thacher Scale above. This is a Gunter Rule for Complex Numbers. The image shows (2+i)x(3+i)=(5+5i). When creating the Scale it is important to keep the Horizontal Scale the same as the Vertical Scale otherwise the answers will be wrong. 

Sector. Not a slide rule but it needs to live somewhere. Multiplication is achieved by setting the linear distance of one multiplier on a pair of dividers then opening the sector such that the distance between two points on the linear scales on opposite sides of the sector is equal to the distance set on the dividers. If the two points are both one for example then between the two occurences of the number two on these scales the distance will be twice that set by the dividers, assuming that the angle between the sector halves is not changed between measurements. 

The Quest kit is also not a slide rule. Each rod has a number printed on it and has a length related to the logarithm of that number with the number 10 rod having a length of 10cm. When rods are laid end to end like those in the centre of the picture, the total length is proportional to the log of the result of multplying together the numbers on the constituent rods. This kit is therefore a good introduction to logarithms and slide rules. It is made by Quest Educational Designs. 

Abbot Brown Tank Capacity Slide Rule made for William Neill and Son Ltd, St. Helens. Abbot Brown is from Beaminster, Dorset, Makers of Engraved and Printed Scales including Slide Rules and Rulers. 

Alan Menmuir Tank Capacity Calculator, made for the Globe Tank & Foundry (Wolverhampton) Ltd. 

Austin Weight Calculator. Double Sharp Weight Calculator, Model A. 

Arel GW Photo Slide Rule. This rule is probably American but I can't prove it so it is staying on this page for now. 

Boots Ring Plan Slide Rule. Boots did not make slide rules they sourced them from both Japan and in this case West Germany. They are displayed here to keep them together. 

Boots Ringplan 5" Standard Slide Rule. Made in Japan. Probably made by Jakar; it is very similar to the Jaker 523A below. 

Boots Ringplan 10" Standard Slide Rule. Made in Japan. Probably made by Jakar; it is very similar to the Jaker 1003A below. 

Boots Ringplan 5" Precision Log Log Slide Rule. Made in Japan. 

Boots Ringplan 10" Precision Log Log Slide Rule. Made in Japan. 

Brinell Hardness Slide Rule, designed by S.A.Main, B.Sc for Hadfield's Ltd, Hecla and East Hecla Works, Sheffield, England. 

The Technical Standard Slide Rule a product of The British Slide Rule Company, proprietors, Marine and Overseas Services Ltd, 16 Barter Street, Holborn, London, WC1 

The Technical Aeronautical Slide Rule a product of The British Slide Rule Company. 

The Supreme Slide Rule a product of The British Slide Rule Company 

Alcohol Proof Rule delivered with Buss Sykes Hydrometer 

Buss 33 Hatton Garden, London, Ullaging Slide Rule with two slides and five piece 48" Ullaging rod the sections of which screw together. The Ullaging rod is used to find the depth of fluid (usually alcoholic beverages) in barrels. Ullage is the empty (airfilled) space above the fluid level in the barrel. 

Classic Series 1. 

Classic Series 1 

Classic Series 2 

Classic Series 2 

Classic Series 3 

Classic Series 4. 

Classic Log Log. A slide rule identical to this has been advertised on EBay as a Classic Series 5; there is no label on the rule but the box was labelled. 

Classic Series 6, Numbers and Percentage Slide Rule. 

Clementson Pipe Sizing Slide Rule. 

Tina's Quarter Square Slide Rule. This is a homemade NonLogarithmic Slide Rule based on the Equation : xy = ((x+y)^2)/4((xy)^2)/4. If you have a set of tables or in this case a slide rule from which the Quarter Squares (w^2/4) of numbers can be found, Multiplication can be achieved solely using Addition and Subtraction. I designed this Slide Rule to Demonstrate this Concept. 

Coggeshall Slide Rule F.B.Cox Maker Warranted Best Box Established 1780 with Scales A[B,C]D a Girt Line and an 8 Square Line (also known as a Mast Maker's Scale) used to set out an Octagon on a Square Timber.. 24" 2Fold rule with 1/8" SubDivisions and 1/4", 3/8", 1/2", 5.8", 3/4" and 1" Scales 

John Davis and Son Derby Ltd, Made in England Slide Rule with scales 10ins//A[B,CI,C]D27cm, [S,L,T]. This rule is very similar in terms of construction method, dimensions and scales to my Stanley Rules which you can see below. This rule has a mode of construction which is different to my other Davis rules leading me to believe that this rule was made by Stanley for Davis. 

John Davis and Son Derby Ltd, Made in England Slide Rule. This rule fits the description of the Davis Autocrat in the pamphlet, John Davis & Son (Derby) Ltd. A Chronology of Slide Rule Production by Colin Barnes. This has scales 10ins//A[B,C]D27cm (extending to 56cm in the well), [S,L,T] with Gunner's gauge marks. 

John Davis and Son Derby Ltd, British Made, Pat.No.232037. Glider Slide Rule. 

John Davis and Son Derby Ltd, Made in England Slide Rule. This rule fits the description of the Davis Autocrat in the pamphlet, John Davis & Son (Derby) Ltd. A Chronology of Slide Rule Production by Colin Barnes. This has scales 10ins//A[B,C]D27cm (extending to 56cm in the well), [S,L,T] with Gunner's gauge marks. This is a copy of the rule above but in better condition. 

John Davis and Son Derby Ltd, British Made, Autocrat. This has the same scale set as the rule above except that it has a 26cm Rule on the side and no extended Centimetre Rule in the Well. 

John Davis and Son Derby Ltd, British Made, Plutocrat. 

John Davis and Son Derby Ltd, British Made, Labelled as an Autocrat but with a Dafield scale set. 

Aristocrat. The Aristocrat was made by Davis and Son but this one has no maker's name. 

Dubilier Capacity Slide Rule Designed by Philip R. Coursey. There are no makers marks but it arrived in a Davis style box and has Davis style construction. The Science Museum describes it as a Davis Rule. 

John Davis and Son Derby Ltd, British Made, Murgatroyd's Percentage Calculator, signed by Peter Murgatroyd. 

Sivad Mannheim. Sivad is Davis backwards and Davis themselves have used Sivad as a brand name on some of their other products. This rule may be an example of the Davis Student as described in the pamphlet, John Davis & Son (Derby) Ltd. A Chronology of Slide Rule Production by Colin Barnes. A rule labelled John Davis & Son, Derby, Ltd, Patent 101051, 1918, Rule Slide, 10 Inches Mark 1 was recently sold on EBay, The Sivad rule seems to be a more recent version of this rule. The differences are that the Mark I has S,L,T scales on the back of the slide, has Gunner's Gauge Marks, two cursors and the celluloid is held in place with screws instead of pins. I think this confirms that Sivad is a Davis Brand Name. 

De Havilland Aircraft Company DH 104 Dove Loading Slide Rule 

Dring and Fage 44" Customs and Excise Slide Rule DF43 G6 and Dring and Fage 50" Cask Ullaging Rod DF73 C9. 

Electrical Apparatus Company, Ltd. St. Albans, Herts. E.A.C. Two Part Tariff Calculator, Day Counter and Charge Evaluator. 

Farmar's Rule, The Standard Slide Rule for the Entire Wine and Spirit Trade (Pocket Size) 

Farmar's Rule, The Standard Slide Rule for the Entire Wine and Spirit Trade (Desk Size) 

Farmar's Rule, The Standard Slide Rule for the Entire Wine and Spirit Trade (Desk Size) 

Farmar's Profit Calculating Rule, a Business Slide Rule for Pricing, Buying and Selling. 

Farmar's Profit Calculating Rule, a Business Slide Rule for Pricing, Buying and Selling. This is a simplified version of the rule shown above. 

Froude Displacement Slide Rule made by Stanley, with two slides, one on each face 

Heath & Co. Hezzanith Navigation Slide Rule. This rule is very similar to the Thornton PIC 3654 which you can see on the Thornton page. The differences are the navigation tables on the back and in the well of the Hezzanith and the inclusion of a reciprocal scale in the centre of the slide on the 3654. The 3654 also has a better quality steel and glass cursor. 

Heath & C0. Hezzanith Carmody Slide Rule 

Helix A50 LL. This rule is definitely not British, it is marked foreign, most of the evidence suggests that it is Japanese but it also shares similarities with some German rules so for now it can stay here. It is identical to the Regal A50LL suggesting that rule is not British either. 

Helix A50 S. This rule is definitely not British, it is marked foreign, most of the evidence suggests that it is Japanese but it also shares similarities with some German rules so for now it can stay here. 

Helix Top Precision No.A102S. This rule is definitely not British, it is marked foreign, most of the evidence suggests that it is Japanese but it also shares similarities with some German rules so for now it can stay here. 

Helix U 02. Made in Japan but shown here to keep it with the other Helix rules. 

Helix U 07. 

Cardboard Slide Rule delivered with Chas. Hoare's Slide Rule Manual 

Cardboard Slide Rule delivered with the 1868 Edition of Chas. Hoare's Slide Rule Manual 

H.S and Company, Two Foot, Four Fold Boxwood Carpenter's Rule. On one face there is a 2 foot scale delineated in Inches, on one edge is a 2 foot scale delineated in 1/100ths of a foot. On the other side, one fold is occupied by a load table from 12 to 24 pence per cubic foot with prices in pounds, shillings and pence for a 50 Cubic feet full load; the adjacent fold has a two decade logarithmic scale and similarly delineated brass slide for calculation with an adjacent Girt Line running from 4 to 40 for calculating the volume of Timber in the Round. The remaining two folds are occupied by scales labelled 1/4, 3/8, 1/2, 5/8, 3/4, Inch, 1 1/4 and 1 1/2. 

Jackson Brothers Limited Armley Leeds 

Jackson Brothers Limited Armley Leeds 

Kitchen Slide Rule. 

MAR Capacity Calculator for Circular and Rectangular Tanks 

Lawes Rabjohns Ltd, Miles Druce and Co. Ltd. Weight Calculator for Iron and Steel Bars, Sections, Joists, Plates and Sheets 

J.A.Nicholl and Company, London, 1916, Mark VI Slide Rule for the Observation of Fire Apparatus used by an Artillery observer to direct fire 

Norton and Gregory, System Rietz. D.R.Patent No. 173660. Based on the patent number this was probably made by Nestler. 

Rabone and Sons Limited TwoFold 24" Rule with Brass Slide made to Slater's pattern for the textile industry. This rule is most similar to Rabone's No.2433 in the 1878 Price List. 

Rabone and Sons Limited, Two Fold 24", Coggeshall Style. This rule is most similar to Rabone's No.2418 in the 1878 Price List. The labels Buck & Hickman Ltd. London and G.M.T.S are also stamped into the surface of this rule. 

Regal A102S, an identical slide rule appeared on EBay recently described as being produced by Regal Harcote Limited. 

Regal A50LL. 

Regal F106. 

Reliance Slide Rule. 

F.Riley Slide Rule. An unusual scale set, A/LogLog C/D with cm and inch scales on the edges and x1/2, x1 1/2 Scale rulers and tables of Sines and Tangents on the reverse side. 

F. Robson, Newcastle on Tyne, This has Scales on both Faces, with A, B and Girt Line Scales on one Face and Inverted Line (Reciprocal) B and A Scales on the other Face. The two edges have 24 Inch Scales. One of the Brass Straps is Engraved with the words Permanent Way Department Wearmouth. 

Short & Mason Atmospheric Humidity with scales Based on Marvin's Tables (USA) Sling/Assmann and on British Met.Office Tables. Stevenson Screen. 

Simplon BiLateral S.B.5 

Simplon S.P.5 

Simplon Slide Rule S.R.10 BiLateral (Reitz System) Patent No. 413308 

Simplon Electro 

Simplon Slide Rule X.L.10 BiLateral (LogLog) Patent No. 413308 

Simplon Major (LogLog) Slide Rule Patent No. 413308 

Simplon Primary (LogLog) Slide Rule (patent No. 413308) Made in England by Dargue Brothers Ltd. New Simplon Works, South Parade, Halifax, England 

Simplon BiLateral Log Log 

Simplon Service WR2A, Patent No. 413308. 

Stanley Slide Rule with scales 10in//A[B,C]D26cm, [S,L,T] 

Stanley Slide Rule with scales 10in//A[B,C]D27cm, [S,L,T] 

The Stanton Ironworks Company Limited, Near Nottingham, England, Water Flow Calculator. Made by P.J.S. 

The M.T.Slide Rule, J.H.Steward Ltd. 406 Strand London. For Calculating the Speed of Columns of Vehicles. 

Rule Slide R.A.(Royal Artillery), J.H.Steward Ltd. 406 Strand London.This rule is marked as formerly being owned by the Captain and Adjutant of the 302nd Field Regiment, Pembrokeshire Yeomanry T.A. This is marked as a PIC rule and is similar to one in my British Thornton collection. 

Taskmaster Linear Slide Rule, made in Leicester. Useful for demonstrating the mode of use of a slide rule to small children. 

Techniculture Calculator. Not a Slide Rule but interesting nevertheless. 

Thomas Hart, The Lambeth Cotton Rope Horse Power Calculator. 

Thomlinson's Equivalent Paper Slide Scale, J.Thomlinson Ltd. Publishers, Partick, Glasgow. 

Tie Clip in the shape of a Slide Rule with moveable slide and cursor. 

Classroom Demonstration Slide Rule 5 Feet 6 Inches Long, Unknown Maker but could be Tiger Toys. 

Unknown Slide Rule purchased in Britain but with design details which suggest it may be an early Nestler of German origin. 

Vickers Machine Gun Slide Rule 

Wheaton, Exeter Slide Rule with scales 26cm//A[B,C]D10in, [S,L,T] L, unlabelled 

Wills Brothers Company, Routledge, Bolton Engineer's Rule 