compass/caliper (UNCLASSIFIED)

Mullins, Bill AMRDEC Bill.Mullins at US.ARMY.MIL
Fri May 6 15:24:35 UTC 2011

Classification: UNCLASSIFIED
Caveats: NONE

The website and electronic catalog for Starrett has a great deal of info
for calipers (you were pretty comprehensive, but left out hermaphrodite

The class of calipers that makes inside/outside measurements and is
somewhat similar in appearance to a slide rule is called "slide
calipers", and includes electronic, vernier and dial measuring

> -----Original Message-----
> From: American Dialect Society [mailto:ADS-L at LISTSERV.UGA.EDU] On
Behalf Of
> victor steinbok
> Sent: Tuesday, May 03, 2011 6:33 AM
> Subject: compass/caliper
> ---------------------- Information from the mail header
> -
> Sender:       American Dialect Society <ADS-L at LISTSERV.UGA.EDU>
> Poster:       victor steinbok <aardvark66 at GMAIL.COM>
> Subject:      compass/caliper
> -
> Some observations on compasses and calipers, although my experience
> these is by no means universal (and, I am sure, under many
circumstances ca=
> n
> be seen as wrong or incomplete)
> I came across a Supreme Court phrase that I wanted to check and looked
> "compass" in the OED.
> In addition to bringing possession *within the statute=E2=80=99s
compass*, =
> Congress
> > increased the severity of =C2=A7924(c) sentences by changing
> e mandatory
> > sentences into mandatory minimum sentences,=E2=80=9D United States
v. O=
> =E2=80=99Brien, 560
> > U. S. ___, ___, and by elevating the sentences for brandishing and
> > discharging a firearm and for repeat offenses. Congress also
> > the provision, =E2=80=9Cdivid[ing] what was once a lengthy principal
> ence into
> > separate subparagraphs,=E2=80=9D id., at ___, and it added the
> xcept=E2=80=9D clause at
> > issue. Pp. 5=E2=80=938.
> [emphasis added]
> There is nothing new or noteworthy in the SCOTUS sentence, but as I
> reading the definitions, I came across this description for
> Compass":
> 4.a. An instrument for taking measurements and describing circles,
> > consisting (in its simplest form) of two straight and equal legs
> d
> > at one end by a movable joint. *Now gen. in pl.; also pair of
> Modifications of this instrument are
> > the bow-compasses (see bow-compass n.); beam-, calliper-
> > etc. Similar instruments for describing figures other than circles
> > specified by a corresponding adj., aselliptic, oval, triangular
> ;
> > also proportional compasses: see these adjs.
> [Emphasis added, where formatting has otherwise been stripped.]
> There are two sets of examples attached to this definition,
> respectively, in 1841 and 1840. The first set is examples with
> "compass", the second with plural "compasses". I have no problem
> both possibilities, but I take issue with the claim "Now gen. in pl.".
> time period is described by "Now"? The 1840s?
> On the other hand, under "Calliper", the first definition describes
> "calliper compasses":
> 1.a. Originally used attrib., calliper compasses or compasses
> > compasses used to measure the calibre of shot; *afterwards usually
> > pl. callipers,pair of callipers*: A kind of compasses with bowed
legs for
> > measuring the diameter of convex bodies; often with a scale attached
> > reading off the measurements; also a similar instrument with
straight leg=
> s
> > and points turned outwards for measuring the bore or internal
diameter of
> > tubes, etc.
>  b. Applied to measuring rules of varying shape for taking the
dimensions o=
> f
> > other than round bodies.   calliper-square n. a rule or square
> > movable cross-heads, adapted for the measurement of internal and
> > diameters or sizes.
>  [Emphasis added, where formatting has otherwise been stripped.]
> Again, the claim is that it's "usually in pl." Here the issue is
> different because the definition (and citations) has not been upgraded
> e
> 1876.
> Both seem wrong but for entirely different reasons.
> One would be hard-pressed to find a commercial product called
> And you will never see or hear "student compasses", except in
reference to
> multiple instantiations of such products. In fact, most "mathematical
> compasses" today are such "student compasses". Most office stores will
> r
> multiple versions of a "student compass" and one or two versions of a
> "professional compass". Most are still instances of a "bow compass",
but th=
> e
> description is usually just limited to a single word. Some are the
> prototypical kind, either with an adjustment wheel or without (some
> the "wheel" on top rather than in the middle).
> Here are a couple of examples of a different kind:
> I'm not entirely sure if the original "student compass"--the
"retarded" bow
> compass with one leg replaced by a loop to hold a pencil or a pen--is
> example of a "bow compass". But it's a fairly standard product that
> squarely under the definition cited above. But it certainly does not
> generally" appear in plural.
> You also will never hear the plural version of "construction with
> straightedge and compass". In fact, having more than one compass would
> a somewhat different implication, although one that has little effect
on th=
> e
> outcome of such constructions. In general, in school settings, I doubt
> e
> is much talk of "compasses"--at least, in the US. Don't know about the
> of the Anglophones.
> I am not sure when and under what circumstances "calliper" lost one of
> ls. But most references today--in US, at least--use "caliper". Typical
> "caliper" is pictured here:
> Often referred to as "vernier caliper", the slightly more traditional
> has a nomographic sliding scale rather than a digital display--a kind
of a
> primitive slide-rule for measurements. Another version uses a dial.
> particular kind of universal/slide caliper measures both interiors
> upper jaws) and exteriors (lower large jaws) of cylindrical/tubular
> ,
> depths of holes (the slide-out depth-probe), as well as just general
> distances and sizes. However, these do not match either 1.a. or
> former only applies to "compasses" (see immediately below) and the
latter i=
> s
> not meant merely "for taking the dimensions of other than round
> bodies"--there is absolutely nothing wrong with using vernier calipers
> measuring round or spherical bodies. In fact, all three examples under
> refer to slide calipers for measuring diameters--something vernier
> have always been uniquely suited for!
> 1708    J. Kersey Dict. Anglo-Britannicum,   Callipers, an instrument
> > like a Sliding-Rule, to embrace the two Heads of a Cask, or Barrel,
in or=
> der
> > to find the length of it.
> 1876    Catal. Sci. Appar. S. Kens. No. 293,   Collection of Timber
> > Callipers for the use of foresters.
> > 1888    N.E.D. at Calliper,   Mod. techn. Calliper (in Liverpool
> > yards), a rule for measuring timber, something like that which
> > use to measure feet.
> The older styles of cal(l)ipers are inside/outside calipers pictured
in Wik=
> i
> here
> These two and vernier calipers can be seen here
> These look like primitive compasses with bent legs and are still in
use for
> quick comparisons where the vernier calipers are impractical. These
> exactly the two kinds of "calliper compasses" that are described under
> caliper 1.a. (see above).
> I often see references to each of these as "calipers" rather than
> "caliper", although both appear to be in use. I saw these recently in
> local lumber store with plural "calipers" on the package. But the Wiki
> article uses singular "caliper" throughout.
> To make matters slightly worse, the latest (1876) example under 1.a.
> actually refers to patented vernier caliper and should appear instead
> 1.b.!
> 1876    Catal. Sci. Appar. S. Kens. No. 284,   Universal Calliper,
> > slide and reverse action. No. 271 Calliper with Dial=E2=80=A5divided
>  eighths of
> > an inch.
> The fourth type of calipers is "divider caliper" (also in Wiki), which
> normally used just as "divider". These are usually seen in movies when
> characters are measuring distances on marine maps. But I'm used to
these as
> separate student implements occasionally confused with compasses--a
> is essentially a compass with the graphite lead replaced with a second
> needle, although many are integral. To be honest, I can't think of
> referring to one of these as "cal(l)iper(s)", so I can't really say
with an=
> y
> certainty whether these appear as singular or plural when they are
> to as such.
> Finally, there is also a micrometer caliper, usually referred to as
> "micrometer" alone or "micro-caliper" or "micro[meter]-gauge" (also in
> under "micrometer"). These are structurally different from the
> universal/slide calipers as they use a handle-based thumb-screw to
> the measuring jaws on the unsuspecting part. I've also heard
references to
> both "caliper" and "calipers" for micrometers in shops and labs.
> Whatever the case, both OED claims that "[mathematical] compass" and
> cal(l)iper" are "now" and "usually" used as plurals appear to be
> significantly overstated, at best--at least, when it comes to US
> British usage might be similar to the math/maths distinction. I have
> idea. I suspect, I would have found more references to such had it
been the
> case. So the definitions for both need adjustment and expansion--they
> seem to be stuck in something like 1876.
> Another odd thing is that "compass" in the sense of "compass rose" is
> listed. Nor, in fact, is there a separate entry for "compass rose" at
> The only mention is under rose 13.a.
> > 13.a. A circular pattern showing the thirty-two points of the
> > compass; spec. the card of a mariner's compass (now usu. compass
rose) or=
>  of
> > a barometer. Cf. wind-rosen. 2.
> If it's "now usu. compass rose", should the "compass rose" have a
> entry or, at least, a compounds under "compass"? And, in fact,
references t=
> o
> it as a "compass" (as in, a picture of a compass) rather than a "rose"
> far more common. So the omission is puzzling.
> VS-)
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Classification: UNCLASSIFIED
Caveats: NONE

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