Walker, Charles Vincent, 1812 - 1882 (electrical engineer)
Person
Found in 58 Collections and/or Records:
File
Astronomical methods and instruments, 1871 - 1873
File
Reference Code: GBR/0180/RGO 6/173
Scope and Contents
Letters and papers concerning new inventions; trials of existing and improved instruments, especially the transit circle, altazimuth and equatorial telescopes; improved techniques; and adjustments to various instruments. The correspondents include W.H.M. Christie, G.G. Stokes, J. Glaisher, Sir D. Gill, C.V. Walker, G.M. Whipple, W. De La Rue, W. Huggins, A.C. Ranyard, F.A.T. Winnecke, J.T.R. Robinson, A.V. Auwers, A. d'Abbadie, Y. Villarceau, J.R. Hind, W.B. Clarke and Sir W. Thomson. There...
Dates:
1871 - 1873
Conditions Governing Access:
From the Management Group:
Unless restrictions apply, the collection is open for consultation by researchers using the Manuscripts Reading Room at Cambridge University Library. For further details on conditions governing access please contact mss@lib.cam.ac.uk. Information about opening hours and obtaining a Cambridge University Library reader's ticket is available from the Library's website (www.lib.cam.ac.uk).
File
Cards of visitors, 1835 - 1852
File
Reference Code: GBR/0180/RGO 6/712
Scope and Contents
Personal and business cards of visitors to the Royal Observatory, including B. Donkin, J.V. Lamont, C.V. Walker, W. Siemens, W.H. Smyth, A. d'Abbadie, R.C. Carrington, G.P. Bond, B.A. Gould, W. Cassell and C. Brennicke. A large proportion of the cards belonged to foreign visitors.
Dates:
1835 - 1852
Conditions Governing Access:
From the Management Group:
Unless restrictions apply, the collection is open for consultation by researchers using the Manuscripts Reading Room at Cambridge University Library. For further details on conditions governing access please contact mss@lib.cam.ac.uk. Information about opening hours and obtaining a Cambridge University Library reader's ticket is available from the Library's website (www.lib.cam.ac.uk).
File
Correspondence on chronometers, 1872 - 1875
File
Reference Code: GBR/0180/RGO 6/603
Scope and Contents
Correspondence on the rates of, repairs to, damage to, ownership of, conversions to, and carriage of various chronometers. The volume covers the Burdett-Coutts prize essay for a compensation balance; problems with the Portsmouth sidereal clock; and proposals for a new electric turret clock at the University of London. The correspondents include F.J.O. Evans, H.C.G. Rümker, C.A.F. Peters, G.H. Richards, C. Wheatstone, C.V. Walker and W.B. Carpenter.
Dates:
1872 - 1875
Conditions Governing Access:
From the Management Group:
Unless restrictions apply, the collection is open for consultation by researchers using the Manuscripts Reading Room at Cambridge University Library. For further details on conditions governing access please contact mss@lib.cam.ac.uk. Information about opening hours and obtaining a Cambridge University Library reader's ticket is available from the Library's website (www.lib.cam.ac.uk).
File
Correspondence on galvanic communications, 1849 - 1853
File
Reference Code: GBR/0180/RGO 6/610
Scope and Contents
Correspondence and related papers concerning the establishment of galvanic communications between the Greenwich and Paris observatories. The papers include extracts from Airy's report on galvanic communications to the Admiralty; the laying of telegraph wires in the grounds of Greenwich Park, illustrated with a plan; the laying of telegraph wires on the South Eastern Railway between London Bridge and Dover; a plan and description of the electric telegraph employed on the South Eastern...
Dates:
1849 - 1853
Conditions Governing Access:
From the Management Group:
Unless restrictions apply, the collection is open for consultation by researchers using the Manuscripts Reading Room at Cambridge University Library. For further details on conditions governing access please contact mss@lib.cam.ac.uk. Information about opening hours and obtaining a Cambridge University Library reader's ticket is available from the Library's website (www.lib.cam.ac.uk).
File
Correspondence on galvanic signals, 1852 - 1855
File
Reference Code: GBR/0180/RGO 6/611
Scope and Contents
Correspondence with the South Eastern Railway and the Electric Telegraph Company and related papers concerning galvanic signals. The papers cover the trials of the Greenwich Mean Time signal between Greenwich and London and Greenwich and Dover, and proposals for and implementation of an extension to the central Telegraph Office, Lothbury, London. There is also correspondence with the Electric Telegraph Company on the time ball service in the Strand, activated from Greenwich by telegraph, and...
Dates:
1852 - 1855
Conditions Governing Access:
From the Management Group:
Unless restrictions apply, the collection is open for consultation by researchers using the Manuscripts Reading Room at Cambridge University Library. For further details on conditions governing access please contact mss@lib.cam.ac.uk. Information about opening hours and obtaining a Cambridge University Library reader's ticket is available from the Library's website (www.lib.cam.ac.uk).
File
Correspondence on galvanic time, 1849 - 1855
File
Reference Code: GBR/0180/RGO 6/612
Scope and Contents
Correspondence on the communication of time by telegraph to Exeter, Norwich, the Bank of England, Portsmouth, Plymouth and Southampton. The papers include complaints about alleged inaccuracies of the Liverpool Time Ball; a request for a clock for the Greenwich Hospital School Observatory; galvanic regulations of the clocks at the General Post Office and the Athenaeum; and the construction of sympathetic galvanic clocks. The correspondents include C.V. Walker, J.C. Clark, S.H. Northcote, G....
Dates:
1849 - 1855
Conditions Governing Access:
From the Management Group:
Unless restrictions apply, the collection is open for consultation by researchers using the Manuscripts Reading Room at Cambridge University Library. For further details on conditions governing access please contact mss@lib.cam.ac.uk. Information about opening hours and obtaining a Cambridge University Library reader's ticket is available from the Library's website (www.lib.cam.ac.uk).
File
Correspondence on galvanic time, 1855 - 1858
File
Reference Code: GBR/0180/RGO 6/613
Scope and Contents
Correspondence and related papers on the communication of time by the Post Office telegraph. There are papers on the trials, costs and tests of clocks on the network; the regulation of clocks; proposals for time signals to be sent to naval dockyards from Greenwich; time balls at Portsmouth, Devonport, Sheerness, Glasgow, Hamburg, Liverpool and the City Observatory, London; and a report by Airy on the workings of the Devonport Time Ball and sketches of its galvanic arrangement. The...
Dates:
1855 - 1858
Conditions Governing Access:
From the Management Group:
Unless restrictions apply, the collection is open for consultation by researchers using the Manuscripts Reading Room at Cambridge University Library. For further details on conditions governing access please contact mss@lib.cam.ac.uk. Information about opening hours and obtaining a Cambridge University Library reader's ticket is available from the Library's website (www.lib.cam.ac.uk).
Sub-Series
Correspondence on geodesy, 1862 - 1868
Sub-Series
Reference Code: GBR/0180/RGO 6/423
Scope and Contents
Correspondence on geodesy with related papers. The correspondents include H. James, W. De La Rue, C. Pritchard, B.A. Gould, O. Struve, F.A.T. Winnecke, C.F. Varley, W.G. Armstrong, J.T. Chance, W. Smyth, A.R. Clarke, R.L.J. Ellery, J.J.V. Littrow, A. d'Abbadie and C.V. Walker. There is material concerning experiments to find the Earth's density; a paper on a geological survey of Britain; drawings of two portable transit instruments and a zenith sector; departmental orders for a...
Dates:
1862 - 1868
Conditions Governing Access:
From the Management Group:
Unless restrictions apply, the collection is open for consultation by researchers using the Manuscripts Reading Room at Cambridge University Library. For further details on conditions governing access please contact mss@lib.cam.ac.uk. Information about opening hours and obtaining a Cambridge University Library reader's ticket is available from the Library's website (www.lib.cam.ac.uk).
File
Correspondence on the Deal Time Ball, 1877 - 1913
File
Reference Code: GBR/0180/RGO 7/255
Scope and Contents
Report from G. Criswick regarding his visit to Deal to examine the apparatus of the time ball, 1877.Report from G. Criswick regarding his visit to Deal to examine the apparatus of the time ball, 1881.Letters concerning the sanitary alterations made at the Deal Time Ball tower, 1879.Letters regarding the widening of the roadway running past the Deal Time Ball tower, 1880.Correspondence with C.V. Walker regarding the failure of time signals,...
Dates:
1877 - 1913
Conditions Governing Access:
From the Management Group:
Unless restrictions apply, the collection is open for consultation by researchers using the Manuscripts Reading Room at Cambridge University Library. For further details on conditions governing access please contact mss@lib.cam.ac.uk. Information about opening hours and obtaining a Cambridge University Library reader's ticket is available from the Library's website (www.lib.cam.ac.uk).
File
Correspondence on the Deal time ball, 1852 - 1855
File
Reference Code: GBR/0180/RGO 6/619
Scope and Contents
Correspondence regarding the time ball at Deal, much of it concerning the construction of the station. The correspondents include Sir F. Beaufort, J.T. Walker, W. Richards and A. Hall. The papers include a diagram of triangulation between St Peters, Thanet, Dover Castle and Paddlesworth.
Dates:
1852 - 1855
Conditions Governing Access:
From the Management Group:
Unless restrictions apply, the collection is open for consultation by researchers using the Manuscripts Reading Room at Cambridge University Library. For further details on conditions governing access please contact mss@lib.cam.ac.uk. Information about opening hours and obtaining a Cambridge University Library reader's ticket is available from the Library's website (www.lib.cam.ac.uk).
File
Correspondence on the Deal time ball, 1855 - 1858
File
Reference Code: GBR/0180/RGO 6/620
Scope and Contents
Correspondence with J. Washington, J.C. Clark and C.V. Walker and others regarding the time ball at Deal. There is also a plan of the magnets of the Deal Time Ball and two maps of the South Eastern Railway and connecting railways in Europe.
Dates:
1855 - 1858
Conditions Governing Access:
From the Management Group:
Unless restrictions apply, the collection is open for consultation by researchers using the Manuscripts Reading Room at Cambridge University Library. For further details on conditions governing access please contact mss@lib.cam.ac.uk. Information about opening hours and obtaining a Cambridge University Library reader's ticket is available from the Library's website (www.lib.cam.ac.uk).
File
Correspondence on the Deal time ball, 1858 - 1863
File
Reference Code: GBR/0180/RGO 6/621
Scope and Contents
Correspondence on the day to day running of the time ball at Deal, its telegraphic communications with Greenwich, and the transfer of ownership from the Admiralty to the South Eastern Railway. The correspondents include C.V. Walker, J. Washington and C.E. Paget.
Dates:
1858 - 1863
Conditions Governing Access:
From the Management Group:
Unless restrictions apply, the collection is open for consultation by researchers using the Manuscripts Reading Room at Cambridge University Library. For further details on conditions governing access please contact mss@lib.cam.ac.uk. Information about opening hours and obtaining a Cambridge University Library reader's ticket is available from the Library's website (www.lib.cam.ac.uk).
File
Correspondence on the Deal time ball, 1864 - 1868
File
Reference Code: GBR/0180/RGO 6/622
Scope and Contents
Correspondence on the day to day running of the time ball at Deal and its telegraphic communications with Greenwich. There are also papers on the sale of the Deal naval dockyard and time ball; Airy's report on a visit to the Deal Time Ball; instructions and orders for W. Newby, the time ball attendant; and a poster explaining the Deal Time Ball service and the refurbishment of the time ball tower. The correspondents include W.G. Romaine, C.V. Walker and J. Field.
Dates:
1864 - 1868
Conditions Governing Access:
From the Management Group:
Unless restrictions apply, the collection is open for consultation by researchers using the Manuscripts Reading Room at Cambridge University Library. For further details on conditions governing access please contact mss@lib.cam.ac.uk. Information about opening hours and obtaining a Cambridge University Library reader's ticket is available from the Library's website (www.lib.cam.ac.uk).
File
Correspondence on the Deal time ball, 1868 - 1872
File
Reference Code: GBR/0180/RGO 6/623
Scope and Contents
Correspondence on the day to day running of the time ball at Deal and its telegraphic communications with Greenwich. There are instructions on cleaning, repairs and failures of current between the Observatory and Deal, and correspondence with W. Newby, the time ball attendant, and with C.V. Walker.
Dates:
1868 - 1872
Conditions Governing Access:
From the Management Group:
Unless restrictions apply, the collection is open for consultation by researchers using the Manuscripts Reading Room at Cambridge University Library. For further details on conditions governing access please contact mss@lib.cam.ac.uk. Information about opening hours and obtaining a Cambridge University Library reader's ticket is available from the Library's website (www.lib.cam.ac.uk).
File
Correspondence on the Deal time ball, 1873 - 1876
File
Reference Code: GBR/0180/RGO 6/624
Scope and Contents
Correspondence on the day to day running of the time ball at Deal and its telegraphic communications with Greenwich. There are instructions concerning routine work, repairs and failures of current between the Observatory and Deal, and correspondence with W. Newby, the time ball attendant, and with C.V. Walker.
Dates:
1873 - 1876
Conditions Governing Access:
From the Management Group:
Unless restrictions apply, the collection is open for consultation by researchers using the Manuscripts Reading Room at Cambridge University Library. For further details on conditions governing access please contact mss@lib.cam.ac.uk. Information about opening hours and obtaining a Cambridge University Library reader's ticket is available from the Library's website (www.lib.cam.ac.uk).
File
Correspondence on the Start Point time signal, 1858 - 1862
File
Reference Code: GBR/0180/RGO 6/625
Scope and Contents
Correspondence with J. Washington, J.C. Clark, R. Fitzroy, G.H. James, C.V. Walker and others on the proposed time signal at Start Point. There are maps of Start Point; plans of the Light House, tower and proposed buildings at Start Point; a map of Plymouth, Devonport and Stonehouse; a map of Start Point and Start Bay; and calculations of numbers for a train of wheels.
Dates:
1858 - 1862
Conditions Governing Access:
From the Management Group:
Unless restrictions apply, the collection is open for consultation by researchers using the Manuscripts Reading Room at Cambridge University Library. For further details on conditions governing access please contact mss@lib.cam.ac.uk. Information about opening hours and obtaining a Cambridge University Library reader's ticket is available from the Library's website (www.lib.cam.ac.uk).
Sub-Series
Correspondence on time balls and signals, 1866 - 1870
Sub-Series
Reference Code: GBR/0180/RGO 6/616
Scope and Contents
Correspondence and related papers on the time signal and time ball service, including a proposed time ball on Tuskar Rock in the Irish Sea, with a chart; a proposed time signal at Dundee; cable laying on the Great Eastern Railway; a proposed Ipswich Time Ball; the rating and errors of the Westminster and Post Office clocks; a proposed public clock for the City of London; electric clocks for the Adelaide Parliament, Madras (including a drawing) and Colaba Observatory in Bombay (including...
Dates:
1866 - 1870
Conditions Governing Access:
From the Management Group:
Unless restrictions apply, the collection is open for consultation by researchers using the Manuscripts Reading Room at Cambridge University Library. For further details on conditions governing access please contact mss@lib.cam.ac.uk. Information about opening hours and obtaining a Cambridge University Library reader's ticket is available from the Library's website (www.lib.cam.ac.uk).
File
Correspondence on time balls and signals, 1870 - 1875
File
Reference Code: GBR/0180/RGO 6/617
Scope and Contents
Correspondence and related papers on the time signal and time ball service, including the failures of the Greenwich time signal; requests for information on time balls; the establishment of time balls or guns at Queenstown, Sheffield, Bristol and Manchester; a paper by S.P. Langley 'On the Allegheny system of electrical time signals'; experiments with the Post Office chronopher; corrections and errors of the Post Office and Westminster clocks; the system of operation employed by the London...
Dates:
1870 - 1875
Conditions Governing Access:
From the Management Group:
Unless restrictions apply, the collection is open for consultation by researchers using the Manuscripts Reading Room at Cambridge University Library. For further details on conditions governing access please contact mss@lib.cam.ac.uk. Information about opening hours and obtaining a Cambridge University Library reader's ticket is available from the Library's website (www.lib.cam.ac.uk).
File
Correspondence on time balls and signals, 1858 - 1860
File
Reference Code: GBR/0180/RGO 6/614
Scope and Contents
Correspondence and related papers on the time signals at Portsmouth, Devonport and Sheerness and the tests, errors and running of time balls at Gravesend, Newcastle, Liverpool, Glasgow, Mauritius and the Cape of Good Hope. The papers include a newspaper cutting from 'The Gateshead Observer' on the importance of time balls; accounts and reports on the Post Office clocks; papers on the regulation of the London Bridge and Westminster Great Clock; and papers on the regulation of the Edinburgh...
Dates:
1858 - 1860
Conditions Governing Access:
From the Management Group:
Unless restrictions apply, the collection is open for consultation by researchers using the Manuscripts Reading Room at Cambridge University Library. For further details on conditions governing access please contact mss@lib.cam.ac.uk. Information about opening hours and obtaining a Cambridge University Library reader's ticket is available from the Library's website (www.lib.cam.ac.uk).
File
Correspondence on time balls and signals, 1861 - 1866
File
Reference Code: GBR/0180/RGO 6/615
Scope and Contents
Correspondence and related papers on the time signal and the time ball service. There are various papers on the signalling of time by a falling ball or by cannon fire at Birmingham, Cardiff, Devonport, Edinburgh, Glasgow, Madras, Newcastle, Nice and the Palais Royale, Paris; proposals for time balls at Wellington (New Zealand), Ipswich, and Port Elizabeth; proposals for clocks and bells in Worcester; details of local time signals in 'The Scotsman', 'Daily Review', 'Glasgow Daily Herald',...
Dates:
1861 - 1866
Conditions Governing Access:
From the Management Group:
Unless restrictions apply, the collection is open for consultation by researchers using the Manuscripts Reading Room at Cambridge University Library. For further details on conditions governing access please contact mss@lib.cam.ac.uk. Information about opening hours and obtaining a Cambridge University Library reader's ticket is available from the Library's website (www.lib.cam.ac.uk).
File
Correspondence on visitor admissions, 1855 - 1860
File
Reference Code: GBR/0180/RGO 6/708
Scope and Contents
Correspondence regarding admissions to visit the Royal Observatory. The volume is divided broadly into requests from the Admiralty to visit the Royal Observatory, introductions on behalf of visitors, personal requests to visit the Observatory, questionnaires for visitors, and instructions to assistants to receive visitors. The correspondents include J. Washington, J. Field, W.H. Sykes, J.W. Lubbock, B.A. Gould, J.C. Adams, J.R. Hind, J.E. Grey, J.A. Brown, J.D. Forbes, R. Fitzroy, J....
Dates:
1855 - 1860
Conditions Governing Access:
From the Management Group:
Unless restrictions apply, the collection is open for consultation by researchers using the Manuscripts Reading Room at Cambridge University Library. For further details on conditions governing access please contact mss@lib.cam.ac.uk. Information about opening hours and obtaining a Cambridge University Library reader's ticket is available from the Library's website (www.lib.cam.ac.uk).
File
Correspondence on visitor admissions, 1866 - 1872
File
Reference Code: GBR/0180/RGO 6/710
Scope and Contents
Correspondence regarding admissions to visit the Royal Observatory. The volume is divided broadly into requests by the Admiralty to visit the Royal Observatory, introductions on behalf of visitors, and personal requests to visit the Observatory. The correspondents include H.C.G.G. Lennox, G.H. Richards, F.J.O. Evans, R. Hall, J. Winlock, B.A. Gould, R. Grant, E.J. Stone, A.A. de la Rive, C.T. Bright, J.W. Lubbock, J.C. Adams, E.J. Routh, J. Glaisher, W. De La Rue, W. Farr, the Earl of Rosse,...
Dates:
1866 - 1872
Conditions Governing Access:
From the Management Group:
Unless restrictions apply, the collection is open for consultation by researchers using the Manuscripts Reading Room at Cambridge University Library. For further details on conditions governing access please contact mss@lib.cam.ac.uk. Information about opening hours and obtaining a Cambridge University Library reader's ticket is available from the Library's website (www.lib.cam.ac.uk).
Sub-Series
Correspondence with scientific societies, 1865 - 1868
Sub-Series
Reference Code: GBR/0180/RGO 6/412
Scope and Contents
Correspondence with various scientific societies, with related papers. There are notices and council minutes for the British Association; reports of the Kew Committee; the report of the committee wishing to publish K.L.C. Rümker's stellar observations; papers relating to W.R. Birt's lunar committee; W. Thomson's report on tidal observations; W.R. Grove's address to the 1866 convention; and J.D. Forbes' address to the 1867 convention. Other articles include a description of the Kew...
Dates:
1865 - 1868
Conditions Governing Access:
From the Management Group:
Unless restrictions apply, the collection is open for consultation by researchers using the Manuscripts Reading Room at Cambridge University Library. For further details on conditions governing access please contact mss@lib.cam.ac.uk. Information about opening hours and obtaining a Cambridge University Library reader's ticket is available from the Library's website (www.lib.cam.ac.uk).
Sub-Series
Correspondence with telegraph companies, 1860 - 1866
Sub-Series
Reference Code: GBR/0180/RGO 6/630
Scope and Contents
Correspondence with various telegraph companies concerned mainly with the failure of time signals, the refurbishment and repairs of wires, the connections with the Royal Observatory, and the trials of overhead wires. There are papers regarding tests on the Dartford Earth current wires; the damage and restoration of telegraph wires due to snowstorms; Airy's details of telegraphic equipment and methods employed at the Royal Observatory, found in 'Description of the galvanic connexions'; a...
Dates:
1860 - 1866
Conditions Governing Access:
From the Management Group:
Unless restrictions apply, the collection is open for consultation by researchers using the Manuscripts Reading Room at Cambridge University Library. For further details on conditions governing access please contact mss@lib.cam.ac.uk. Information about opening hours and obtaining a Cambridge University Library reader's ticket is available from the Library's website (www.lib.cam.ac.uk).
File
Correspondence with tradesmen, 1850
File
Reference Code: GBR/0180/RGO 6/723
Scope and Contents
Correspondence with tradesmen, including letters from booksellers; coal merchants; horologists; builders; chandlers; merchants; draughtsmen; instrument makers; stationers; the Kent Water Company; parcel carriers; engineers; chemists; photographic suppliers; decorators; the Phoenix Gas Company; journeymen; an ironmonger; a manufacturer of gas appliances; and an upholsterer. The letters cover instructions; requests; accounts; bills; receipts; circulars; tenders; invoices; routine repairs; and...
Dates:
1850
Conditions Governing Access:
From the Management Group:
Unless restrictions apply, the collection is open for consultation by researchers using the Manuscripts Reading Room at Cambridge University Library. For further details on conditions governing access please contact mss@lib.cam.ac.uk. Information about opening hours and obtaining a Cambridge University Library reader's ticket is available from the Library's website (www.lib.cam.ac.uk).
Additional filters:
- Subject
- Telegraphy 16
- Time 15
- Clocks 13
- Electricity 13
- Deal 9
- London 8
- Devonport 5
- Edinburgh 5
- Adelaide 4
- Glasgow 4
- Liverpool 4
- Paris 4
- Dover 3
- India 3
- Ipswich 3
- Longitude 3
- Portsmouth 3
- South Australia 3
- Africa 2
- Atlantic Ocean 2
- Blackheath 2
- Bristol 2
- Cambridge 2
- Chennai 2
- Geodesy 2
- Irish Sea 2
- Manchester 2
- Newcastle upon Tyne 2
- Oxford 2
- Sheerness 2
- Southampton 2
- Vienna 2
- Australia 1
- Baltiysk 1
- Bay of Fundy 1
- Berlin 1
- Birmingham 1
- Bombay 1
- Brussels 1
- Calcutta 1
- Cape of Good Hope 1
- Cardiff 1
- Cat Island 1
- Chicago 1
- Compasses 1
- Cornwall 1
- Cumbria 1
- Córdoba 1
- Dublin 1
- Dundee 1
- East Indies 1
- English Channel 1
- Exeter 1
- France 1
- Fredericton 1
- Geology 1
- Gravesend 1
- Hamburg 1
- Himalayas 1
- Lake District 1
- Leith 1
- Lisbon 1
- Lowestoft 1
- Maastricht 1
- Mauritius 1
- Mechanics 1
- Melbourne 1
- Meteorology 1
- Nice 1
- North Sea 1
- Norwich 1
- Pacific Ocean 1
- Pernambuco 1
- Pevensey 1
- Photography 1
- Plymouth 1
- Port Elizabeth 1
- Potsdam 1
- Quebec 1
- Queenstown 1
- Railway transport 1
- Ramsgate 1
- Severn 1
- Sheffield 1
- Ships 1
- South Africa 1
- Start Bay 1
- Start Point 1
- Stonehouse 1
- Tasmania 1
- Telescopes 1
- Thames 1
- Tyne 1
- United States 1
- Valencia Island 1
- Vesuvius 1
- Wellington 1
- Worcester 1 + ∧ less
∨ more