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August 2017
- 1 -
Overview of A.W. Faber-Castell Slide Rule Dating Chronology 1892-1920
Colin Tombeur
Background This article is one of a series which details the early slide rules of A.W. Faber-Castell (hereafter referred to as Faber). The series, by Trevor Catlow and myself, is based on our research collaboration and the resulting development and analysis of a database of slide rule specimens, as described in [1]. Although Faber began production with just one known slide rule model, they quickly developed their designs, production processes and model range. Due the scarcity of detailed reliable information, dating these slide rules before Faber introduced blind date stamps has been difficult. Trevor’s 2009 JOS article [2] and subsequent 2013 update [3] were the first major steps in rectifying this situation. Although broadly correct, Trevor’s findings were based largely on the limited number of slide rules from this time in his collection. As a result his scope was limited, a fact that he acknowledged in his articles. Our collaboration has produced a more comprehensive chronology of changes to features on these early slide rules, based on the study of many more specimens, cataloguing and dating as many changes as possible. This article gives an overview of feature changes between the beginning of slide rule production in 1892 [4] and the introduction of date stamps on the rules in 1920 [5]. We have been able to supply an approximate year, or span of years, for the changes, which we believe to be accurate to within a year or so. Planned further articles in the series will describe particular areas of focus and the chronology of feature changes in much greater detail.
A slide rule can only be as old as the introduction of its most recent feature, and as young as
the earliest time a feature present on it was phased out. [1] A slide rule without a blind stamp can be given an approximate date range of the completion of its manufacture by comparing and aligning its features with the Chronology Chart below. In theory all of the date ranges of features on a specimen should overlap at some point on the chart and an approximate date of manufacture can easily be established. Occasionally however, due to peculiarities in the design and manufacturing process this is not the case, but a manufacture date can still be estimated using the above guideline from the latest overlapping range of features. Particular care should be taken when considering cursors and boxes which may have been replaced with non-original items. Unless a definite connection can be established, for example by the addition of names or dates by a previous owner, these items should be considered as confirming, rather than defining, the dating. Introducing the Chronology Chart The Chronology Chart has rows detailing slide rule features, grouped into the following five categories: STOCK & SLIDE, SCALES, CURSOR, TEXT & LABELS and BOX. Each feature may have several manifestations. Some of the features have references to chart notes, either a single character for further description, e.g. (a), or two characters for picture examples, e.g. (aa). The columns indicate an approximate year, or year range, when a change occurred, ‘Change Point’, prefixed with ‘c’ (circa). Where it has not been possible to define change points unambiguously for certain features, some year ranges overlap others. Such cases are highlighted in light blue, and special care should be taken when comparing features around these points. In the main body of the chart, features that are present at the change points are indicated by solid green shading. Thus an approximate start point, when the feature first appeared on slide rules, and end point (unless it was ongoing after 1920), when it was phased out, can be determined for each feature. Orange shading indicates an unknown status, where there is insufficient or no evidence to determine whether a feature was present or not. The green shading is either dark, indicating a generic presence across all slide rules
Overview of A.W. Faber-Castell Slide Rule Dating Chronology 1892-1920
- 2 -
current at that time, or one of two lighter shades, indicating that the presence is specific to a certain set of slide rules. Where the presence is specific, the set is indicated inside the shading either with text or, when there is insufficient space, as a reference to a one or two digit chart note (e.g. 10.). Sets are generally models (e.g. ‘350, 360, 365’), model exclusions (e.g. ‘not 350, 360, 365’), languages (e.g. ‘German’, ‘non-German’) or models of certain scale length or construction (e.g. ’50 cm scale’, ‘not 50 cm scale’, ‘all-wood’, ‘not all-wood’). While it is possible to use the chart for dating without knowing a model number, it is easier if the model is known. If present, the model number is the three digit number on the front of the slide rule before the maker’s name. If this number is not present, the model can be quickly established using the guide at the end of this article. Referring to the first few rows of the Chronology Chart, examples of the above conventions for representing specific changes can be seen. In row 1, it is shown that a 15 cm stock length is found only on models with a 12.5 cm scale length, from c1907-8 onwards. Row 2 shows that a 26.4 cm stock was seen only in c1892. The dark green colouration of this cell indicates that “all current models” were of this length (even though in fact only one model actually existed at the time). Row 3 shows that the generic stock length changed to 26 cm in c1892-3. Row 4 shows that stocks with a length of 28 cm were introduced in c1899 for the six models indicated. Referring back to row 3, the 26 cm stock length is no longer generic but specific to models 350, 360 and 365 from this time until c1909 (although this does not define the date of the introduction of these models, see below). In c1907, note 1 indicates that a different subset of models had the 28cm stock, and this subset changed again in c1910. Row 5 shows that the model 368 had a 28.5 cm stock between c1907 and c1910-11. As previously indicated, the dates of the change points are approximate to within a year or so, however some features are known to crossover around specific years, particularly those involving registered designs and patents. In this case, the shading is crosshatched to indicate a possible presence or not in the change point, or a transition to an unknown status. In addition, crosshatching is used where there is potential ambiguity due to an overlap in change points (those highlighted in blue). For example, “Cursor grooves – above both top and bottom edge rulers”. This feature was true of all slide rules from c1903-4 ongoing, with the exception of the 368 from c1906 to c1910-11 when it was withdrawn. Therefore from c1903-4 up to c1906 and from c1911 to the end, this feature is coloured dark green (generic), and the chronological points in-between, c1906 to c1910-11, are light green (specific) with the model 368 indicated. The overlap change points c1908-13, c1910-12 and c1910-13 are crosshatched light and dark green to indicate a crossover in these periods. The chronology is necessarily complex because features can be specific to certain sets of slide rules, or there can be different evolutionary timescales for a particular feature for different sets of rules. In order to simplify, the model specific notes do not necessarily indicate exactly when models were introduced, since this is often unclear. Therefore, generally, the chronology should not be used for this purpose [6]. However some models were introduced with dateable model defining features, for example the 360 with the introduction of celluloid scales, the 367 with its digit registering cursor, and the 368 ‘electro’ model. Our chronology does not claim to be definitive, but Trevor and I believe we have reached a point of stability in our findings. Nevertheless, if any of our readers can provide additional information, please do contact us, our details can be found in the UKSRC membership directory. Assigning Model Numbers to Faber Slide Rules From c1908 to well after 1920 Faber slide rules carried a three digit model number, beginning with a ‘3’, and followed by a ‘*’ before the maker’s name, for example “368 * A.W. FABER.”. Before this, model numbers did not appear on the slide rules themselves although they are known to have existed, appearing in manuals and catalogues, from around 1895 [7]. It is unclear if the very first slide rules made between 1892 and 1895 were assigned model numbers, but examples show marked similarities to the model identified as the 350 in 1895, so for the purpose of identification these first slide rules are also considered as the model 350. For the seventeen models that were in production between 1892 and c1908, and therefore did not carry a model number, this guide enables the number to be determined. Using Table 1 it is easy to identify the model
Overview of A.W. Faber-Castell Slide Rule Dating Chronology 1892-1920
- 3 -
from a few obvious features. Some details of these models changed over time (for example the model 360 changed from a 26 cm length to a 28 cm length) but only after model numbers appeared on them. For certain models the guide depends on the fact that models originating with digital-registering cursors have not lost them. As a check, these rules carried the label ‘DRGM 116832’ until c1905. Starting at the left-hand side of the table, compare the features listed at each stage until reaching the model number at the right-hand side. Features at each stage are mutually exclusive. For example, is the slide rule faced or not faced? If it is not faced, then is the stock less than 28 cm, equal to 28 cm or is the scale 50 cm? If it is 28 cm then is the cursor normal, digit registering or a calliper? If the cursor is digit registering then the slide rule is a model 357.
References & Bibliography [1] Every Slide Rule Tells a Story - Establishing an Early A.W. Faber-Castell Chronology (Colin Tombeur),
United Kingdom Slide Rule Circle (UKSRC), Slide Rule Gazette, Issue 17, Autumn 2017, Page 15 [2] Suggestions for Dating pre-1920 Faber-Castell Slide Rules (Trevor Catlow), Journal of the Oughtred
Society, 18.2, Fall 2009, Page 47 [3] Suggestions for Dating pre-1920 Faber-Castell Slide Rules: an Update (Trevor Catlow), Journal of the
Oughtred Society, 22.1, Spring 2013, Page 45 [4] Slide Rules: A Journey through Three Centuries (Dieter von Jezierski), Astragal Press, 2000 [5] Rechenschieber Slide Rules A.W. Faber A.W. Faber-Castell (Peter Holland), self-publication [6] For a comprehensive compendium of the dates of Faber slide rule models, see [5]. Due to differences in
methodology, dates in this book do not always agree with those in this article. This dating business is not (yet) a fully-defined science, see also [1].
[7] Transition from boxwood to celluloid on boxwood within A.W. Faber (Dieter von Jezierski), United Kingdom Slide Rule Circle (UKSRC), Skid Stick, No. 11, June 2002, Page 7
The Chronology Chart is available in larger printer friendly formats on the UKSRC web site in the Gaz Plus section (uksrc.org.uk/gazplus.html), Gazette 2017 Vol 17, Supplemental Material. A full bibliography of sources used in the development of this article can be found in [1].
Model
350
354
357
358
370
369
360
365
374
377
361
363
366
368
Normal cursor 364
Digit registering cursor 367
380
Not faced
28 cm stock
Celluloid faced
26 cm stock
28-29 cm stock
< 28 cm stock
Normal cursor
Digit registering cursor
Normal cursorScale on back of
stock
No scale on
back of stock
Numbers with
decimal point
Numbers
without decimal
point
Scales on back
of slide
Digit registering cursor
No SLT scales
SLT scales
No scales on back of slide
Table 1 : Faber model identification 1892-c1908
Caliper cursor
50 cm scale
15.5 cm scale
No slide springs
Slide springs
Log-log scales on edge
50 cm scales
No log-log
scales on edge
Overview of A.W. Faber-Castell Slide Rule Dating Chronology 1892-1920
- 4 -
CHRONOLOGY CHART
c1892
c1892-3
c1893-5
c1895
c1896-9
c1898-9
c1899
c1900
c1900-3
c1901
c1901-3
c1903
c1903-4
c1904
c1904-5
c1905
c1905-6
c1906
c1906-7
c1907
c1907-8
c1908
c1908-9
c1908-13
c1909
c1910
c1910-11
c1910-12
c1910-13
c1911
c1912
c1912-13
c1913
c1914
c1914-20
12
.5 c
m s
cale
35
0, 3
60
, 36
5
35
4, 3
57
, 36
3, 3
64
, 36
7, 3
68
1.
no
t 1
2.5
or
50
cm
sca
le o
r 3
68
, 37
8
36
8
37
8
50
cm
sca
le
no
t 3
69
all
-wo
od
no
t a
ll-w
oo
d
no
n-G
erm
an
36
1, 3
66
, 36
9*,
37
4, 3
77
, 37
9, 3
84
Ge
rma
nn
ot
36
1, 3
66
, 36
9*,
37
4, 3
77
, 37
9, 3
84
36
1, 3
66
, 36
8
no
t 3
61
, 36
6, 3
68
no
t 3
68
36
8
36
8
36
1
no
t 3
61
no
t 3
61
, 36
6
no
t 3
50
, 36
0, 3
65
no
t 3
61
, 36
6
no
t a
ll-w
oo
d
no
t a
ll-w
oo
d o
r 3
61
no
t a
ll-w
oo
d
35
4, 3
57
, 36
3, 3
64
, 36
5, 3
67
2.
3.
36
5, 3
78
36
8, 3
78
, 37
9
no
t a
ll-w
oo
d
no
t a
ll-w
oo
d no
t a
ll-w
oo
d o
r 1
2.5
cm
sca
le
c1892
c1892-3
c1893-5
c1895
c1896-9
c1898-9
c1899
c1900
c1900-3
c1901
c1901-3
c1903
c1903-4
c1904
c1904-5
c1905
c1905-6
c1906
c1906-7
c1907
c1907-8
c1908
c1908-9
c1908-13
c1909
c1910
c1910-11
c1910-12
c1910-13
c1911
c1912
c1912-13
c1913
c1914
c1914-20
36
93
69
, 37
9
no
t 3
69
, 37
9, 3
80
, 38
4
38
03
80
, 38
4
op
tio
n o
n 3
60
, 36
3, 3
64
, 36
5, 3
67
all
-wo
od
& 5
0 c
m s
cale
4.
no
t a
ll-w
oo
d o
r 5
0 c
m s
cale
s5
.
all
-wo
od
all
-wo
od
no
t a
ll-w
oo
d
no
t 3
68
6.
7.
36
83
61
, 36
6
no
t 3
61
, 36
6, 3
68
no
t 5
0 c
m s
cale
or
36
1, 3
66
, 36
8, 3
74
, 37
7, 3
78
8.
38
0
8.
Pla
in (n
o r
ail
wa
y tr
ack
s)
Rig
ht
en
d (s
in &
log
sca
les)
Left
en
d (t
an
sca
les)
On
ba
ck o
f sto
ck
On
ba
ck o
f sto
ck a
lign
ed
to
rig
ht
slo
t in
de
x
Top
ed
ge, n
ot
to e
nd
s o
f sto
ck
Bo
tto
m e
dge
no
t to
en
ds
of s
tock
Bo
tto
m e
dge
to
en
ds
of s
tock
On
ba
ck o
f sli
de
In w
ell
Ce
nti
me
tre
ext
en
sio
n
sca
le
Inch
/ce
nti
me
tre
con
vers
ion
sca
le (b
b)
A.W
. FA
BER
-CA
STEL
L SL
IDE
RU
LE F
EATU
RES
18
92
-19
20
STO
CK
& S
LID
E
15
cm
26
cm
26
.4 c
m
28
cm
28
.5 c
m
29
.5 c
m
53
.5 c
m
Ab
ove
to
p e
dge
ru
ler
bu
t sp
lit
bo
tto
m e
dge
ru
ler
Ab
ove
bo
th t
op
& b
ott
om
ed
ge r
ule
rs
An
gle
d in
to s
tock
at
fro
nt/
top
ed
ge jo
in
An
gle
d in
to s
tock
at
fro
nt/
bo
tto
m e
dge
join
Rig
ht
en
d o
f fro
nt
Fla
t b
ack
(no
re
ba
te a
nd
ta
ble
s)
Re
ba
ted
wit
h p
ap
er
tab
les
At
bo
tto
m o
f sli
de
ed
ge
In c
en
tre
of s
lid
e e
dge
Me
tal i
nse
rts
Form
at
of M
an
nh
eim
sca
les
(aa
)
Ch
ise
l in
de
x fo
r w
ell
sca
les
Sto
ck
Sin
gle
ra
ilw
ay
tra
ck
Un
eq
ua
l do
ub
le r
ail
wa
y tr
ack
Do
ub
le r
ail
wa
y tr
ack
Slid
e
Lon
gitu
din
al i
n s
tock
& s
lid
e
SCA
LES
15
cm
Slid
e in
de
x e
nd
(c)
Wo
od
en
fixi
ng
pin
s fo
r
cell
ulo
id
25
cm
Ha
nd
pri
nte
d s
cale
s
Tem
pla
te p
rin
ted
sca
les
Ligh
tly
inci
sed
sca
les
De
ep
ly in
cise
d s
cale
s
Up
pe
r st
ock
ra
il, b
elo
w s
lid
e g
roo
ve
Up
pe
r st
ock
ra
il, i
n s
lid
e g
roo
ve
Sca
le le
ngt
h
Ch
ange
Po
int
Ma
rkin
g m
eth
od
(d)
Ru
lers
on
ed
ges
Spli
t b
oth
ed
ge r
ule
rs
Top
& b
ott
om
ed
ges
25
.2 c
m (a
pp
rox.
)
Len
gth
Sto
ck c
on
stru
ctio
n (a
)
Ba
ck o
f sto
ck
Bo
tto
m e
dge
of s
tock
Cu
rso
r gr
oo
ves
(b)
Slid
e T
hu
mb
No
tch
Slid
e r
un
ne
r
Slo
ts in
ba
ck o
f sto
ck t
o
ind
ex
ba
ck o
f sli
de
Ce
llu
loid
faci
ngs
Bo
xwo
od
sp
rin
gs t
o
ten
sio
n s
lid
e
Sin
gle
pie
ce, s
oli
d
Sin
gle
pie
ce w
ith
2 lo
ngi
tud
ina
l sli
ts in
we
ll
Two
pie
ce, c
ell
ulo
id s
pru
ng
Two
pie
ce, s
tee
l sp
run
g
Be
vell
ed
Pe
rpe
nd
icu
lar
Fro
nt,
we
ll &
fro
nt
& b
ack
of s
lid
e
50
cm
Overview of A.W. Faber-Castell Slide Rule Dating Chronology 1892-1920
- 5 -
c1892
c1892-3
c1893-5
c1895
c1896-9
c1898-9
c1899
c1900
c1900-3
c1901
c1901-3
c1903
c1903-4
c1904
c1904-5
c1905
c1905-6
c1906
c1906-7
c1907
c1907-8
c1908
c1908-9
c1908-13
c1909
c1910
c1910-11
c1910-12
c1910-13
c1911
c1912
c1912-13
c1913
c1914
c1914-20
no
t 3
61
36
79
.a
ll-w
oo
d
all
-wo
od
10
.n
ot
all
-wo
od
or
12
.5 o
r 5
0 c
m s
cale
or
36
61
1.
12
.
13
.
14
.n
ot
12
.5cm
sca
le o
r 3
66
36
8, 3
78
, 37
9
36
8, 3
78
, 37
9
36
8, 3
78
, 37
9
15
.
36
8
36
8, 3
78
, 37
9
37
4, 3
77
36
6
c1892
c1892-3
c1893-5
c1895
c1896-9
c1898-9
c1899
c1900
c1900-3
c1901
c1901-3
c1903
c1903-4
c1904
c1904-5
c1905
c1905-6
c1906
c1906-7
c1907
c1907-8
c1908
c1908-9
c1908-13
c1909
c1910
c1910-11
c1910-12
c1910-13
c1911
c1912
c1912-13
c1913
c1914
c1914-20
no
n-E
ngl
ish
no
n-E
ngl
ish
all
-wo
od
& 5
0 c
m s
cale
no
n-E
ngl
ish
all
-wo
od
Engl
ish
Engl
ish
all
-wo
od
& 5
0 c
m s
cale
Engl
ish
all
-wo
od
no
t a
ll-w
oo
d o
r 5
0 c
m s
cale
no
t a
ll-w
oo
d
35
0, 3
55
, 36
0, 3
61
, 36
3, 3
65
35
0, 3
55
, 36
1, 3
63
17
.1
8.
all
-wo
od
no
t a
ll-w
oo
da
ll-w
oo
d
no
t a
ll-w
oo
d
36
3, 3
67
19
.3
54
, 35
72
0.
50
cm
sca
le &
36
3, 3
64
, 36
7, 3
68
, 37
4, 3
77
21
.2
2.
23
.2
4.
25
.
36
3, 3
67
26
.2
7.
28
.3
63
29
.
`
36
8, 3
78
, 37
9
36
8
no
t a
ll-w
oo
d
no
t a
ll-w
oo
d o
r 1
2.5
cm
sca
le
36
6
37
4, 3
77
37
4, 3
77
Ge
rma
n
Ge
rma
n
Ge
rma
n, n
ot
36
8, 3
69
, 37
8, 3
79
Engl
ish
Engl
ish
, no
t 3
68
, 36
9, 3
78
, 37
9
Styl
e 6
(Fre
nch
)Fr
en
ch, n
ot
36
8, 3
69
, 37
8, 3
79
36
8, 3
78
36
93
69
36
9
Ge
rma
n
No
n-G
erm
an
'DR
P 2
06
42
8' (
19
08
)
Styl
e 2
(Ge
rma
n)
'DR
P 2
15
72
2' (
19
09
)
Ba
ck la
be
l sty
le (b
b)
Ba
ck la
be
l te
xt s
tyle
(dd
)
Ba
ck a
dve
rtis
ing
lab
el
(bb
)
Pa
pe
r
Ce
llu
loid
Styl
e 4
(En
glis
h)
Styl
e 7
(En
glis
h e
lect
ro),
8 (N
on
-En
glis
h e
lect
ro)
Styl
e A
Styl
e B
Styl
e 5
(En
glis
h)
Tem
pla
te p
rin
ted
'Qu
ot.
+1' &
'Pro
d.-
1'
On
left
& r
igh
t u
pp
er
sto
ck e
nd
s
3-d
igit
, fo
llo
we
d b
y '*
' be
fore
bra
nd
Bo
xwo
od
sp
rin
gs in
we
ll fo
r sl
ide
Dig
it r
egi
ste
rin
g cu
rso
r
Syst
em
Pic
kwo
rth
Syst
em
Pic
kwo
rth
Styl
e 1
(Ge
rma
n)
Slid
e e
nd
ind
ex
ed
ge fo
r w
ell
sca
les
Cu
rso
r w
ith
ho
ok
ind
ex
for
ed
ge s
cale
s
Wo
od
fixi
ng
pin
s fo
r ce
llu
loid
Lon
gitu
din
al m
eta
l in
sert
s
Syst
em
Sch
um
ach
er
No
n-E
ngl
ish
/no
n-G
erm
an
lan
gua
ge r
ule
s
'QU
OTI
ENT
+1' &
'PR
OD
UC
T -1
'
De
cim
al n
ota
tio
n
Dis
pla
ced
1.5
/15
on
A &
B s
cale
s
Styl
e A
Styl
e B
Styl
e C
SCA
LES
(co
nti
nu
ed
)
SLT
sca
les
On
ba
ck o
f sli
de
On
A, B
, C &
D
Tick
s o
n M
an
nh
eim
sca
les
(e)
'DR
GM
37
11
90
' (1
90
8)
Bra
nd
typ
efa
ce
Ha
nd
pri
nte
d
Engl
ish
lan
gua
ge r
ule
s
Qu
oti
en
t/P
rod
uct
± o
n
low
er
sto
ck e
nd
s
Ele
ctro
ga
uge
ma
rks
c &
c1
ga
uge
ma
rks
On
A &
B o
nly
'DR
GM
34
45
76
' (1
90
8)
'DR
GM
37
11
89
' (1
90
8)
Scri
pt
M (w
ith
lon
g ta
il) o
n B
on
lyM
ga
uge
ma
rk (c
c)
Log-
log
ind
ex
ma
rks
Syst
em
Pic
kwo
rth
Syst
em
Sch
um
ach
er
Bra
nd
na
me
Nu
mb
ers
on
sca
le
sub
div
isio
ns
(f)
Sca
le n
um
be
rin
g
typ
efa
ce (a
a)
Sca
le n
um
be
rin
g
ma
rkin
g (g
)
Arr
ow
± s
ymb
ols
(aa
)
Mo
de
l nu
mb
er
'DR
GM
98
35
0' (
18
98
)
'DR
GM
11
68
32
' (1
89
9)
'DR
GM
42
75
14
' (1
90
5)
'DR
GM
27
11
69
' (1
90
6)
W o
n r
igh
t e
nd
of C
Cu
be
sca
le a
nd
win
do
w o
n b
ack
of s
tock
No
n-l
oga
rith
mic
sca
les
an
d in
de
xes
TEX
T &
LA
BEL
S
On
D a
s w
ell
as
C
"Dyn
am
o"/
"Mo
tor"
& "
Vo
lt"
sca
les
in w
ell
Me
tric
(28
7 &
73
6 o
n A
& B
sca
les)
Imp
eri
al (
28
7 &
74
6 o
n A
& B
sca
les)
Un
lab
ell
ed
on
no
n-e
lect
ro r
ule
s
Ele
ctro
sca
les
Styl
e 3
(Ge
rma
n)
Ori
gin
('M
AD
E IN
…')
'A.W
. Fa
be
r'
'A.W
. Fa
be
r "C
ast
ell
"'
Go
ld s
eri
f
Go
ld s
an
s-se
rif
Bla
ck s
an
s-se
rif
2.9
on
left
& r
igh
t e
nd
s o
f D
San
s-se
rif M
on
A &
B
Scri
pt
M (w
ith
lon
g ta
il) o
n A
& B
Seri
f M o
n A
& B
Overview of A.W. Faber-Castell Slide Rule Dating Chronology 1892-1920
- 6 -
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34
3
36
7, 3
77
, 38
0
16
.
36
7, 3
68
, 37
7, 3
80
36
8
36
8
c1892
c1892-3
c1893-5
c1895
c1896-9
c1898-9
c1899
c1900
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c1901
c1901-3
c1903
c1903-4
c1904
c1904-5
c1905
c1905-6
c1906
c1906-7
c1907
c1907-8
c1908
c1908-9
c1908-13
c1909
c1910
c1910-11
c1910-12
c1910-13
c1911
c1912
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c1913
c1914
c1914-20
50
cm
sca
le
no
t 5
0 c
m s
cale
no
t 5
0 c
m s
cale
Engl
ish
Ge
rma
n
Engl
ish En
glis
h
Engl
ish
Engl
ish
Ch
art
No
tes
(re
fer
to t
ext
for
mo
re d
eta
il):
Ge
ne
ric
Spe
cifi
cN
ot
kno
wn
(a
)A
ll s
tock
s in
th
is t
ime
fra
me
we
re m
ad
e fr
om
wo
od
. In
itia
lly
the
tw
o s
tock
ra
ils
an
d w
ell
we
re fo
rme
d fr
om
on
e s
oli
d p
iece
. Tw
o
lon
gitu
din
al s
lits
we
re in
tro
du
ced
into
th
e w
ell
th
at
usu
all
y p
en
etr
ate
bo
th t
he
so
lid
wo
od
en
sto
ck (w
hic
h m
ay
be
co
vere
d o
n t
he
Cro
sso
ver
Ove
rla
p in
ch
an
ge p
oin
tsb
ack
wit
h a
pa
pe
r la
be
l) a
nd
th
e c
ell
ulo
id fa
cin
g in
th
e w
ell
(if p
rese
nt)
, occ
asi
on
all
y th
ey
are
on
ly in
th
e w
oo
d.
A t
wo
pie
ce
cell
ulo
id s
pru
ng
sto
ck is
dis
tin
guis
he
d b
y a
n e
nd
-to
-en
d lo
ngi
tud
ina
l sp
lit
in t
he
wo
od
of t
he
we
ll o
f th
e s
tock
wit
h n
o
corr
esp
on
din
g sp
lit
in t
he
ce
llu
loid
faci
ng
in t
he
we
ll.
A s
tee
l sp
run
g st
ock
is d
isti
ngu
ish
ed
by
an
en
d-t
o-e
nd
lon
gitu
din
al s
pli
t in
1.
35
4, 3
55
, 35
7, 3
63
, 36
4, 3
67
16
.3
67
, 37
7, 3
80
bo
th t
he
wo
od
an
d t
he
the
ce
llu
loid
faci
ng
(if p
rese
nt)
of t
he
we
ll.
2.
35
4, 3
55
, 35
7, 3
63
, 36
4, 3
65
, 36
7, 3
68
, 37
4, 3
77
, 37
81
7.
35
0, 3
55
, 36
0, 3
61
, 36
3
(b)
Cu
rso
r gr
oo
ves
wil
l eit
he
r: s
pli
t a
n e
dge
ru
ler
(nu
mb
ers
ab
ove
gro
ove
an
d d
ivis
ion
s b
elo
w) a
nd
be
pe
rpe
nd
icu
lar
to t
he
ed
ge fa
ce;
3.
35
4, 3
55
, 35
7, 3
63
, 36
4, 3
65
, 36
7, 3
74
, 37
7, 3
78
18
.3
50
, 35
5, 3
61
, 36
3b
e e
nti
rely
ab
ove
a r
ule
r a
nd
pa
rall
el t
o t
he
to
p fa
ce o
f th
e r
ule
; be
an
gle
d in
to t
he
sto
ck a
t th
e jo
in o
f th
e t
op
an
d e
dge
face
s.
4.
no
t 1
2.5
cm
sca
le o
r 3
66
19
.3
63
, 36
4, 3
67
(c
)Sl
ide
is s
ligh
tly
sho
rte
r th
an
sto
ck w
ith
an
alu
min
ium
ind
ex
ed
ge f
or
rea
din
g th
e s
cale
s in
th
e w
ell
.
5.
12
.5 c
m s
cale
& 3
66
20
.3
54
, 35
7
(d)
Ha
nd
pri
nte
d s
cale
s a
re s
mo
oth
on
th
e fa
ce o
f th
e r
ule
an
d e
xhib
it r
an
do
m m
ark
ing
dif
fere
nce
s fr
om
be
ing
dra
wn
fro
m a
pa
tte
rn.
6.
no
t 3
61
, 36
82
1.
50
cm
sca
le &
36
3, 3
64
, 36
5, 3
67
, 36
8, 3
74
, 37
7Te
mp
late
pri
nte
d s
cale
s a
re a
lso
sm
oo
th, b
ut
dif
fere
nce
s a
re c
on
sist
en
t. L
igh
tly
inci
sed
sca
les
sho
w a
fain
t te
xtu
re w
he
n a
7.
no
t 3
61
22
.5
0 c
m s
cale
& 3
63
, 36
4, 3
65
, 36
7, 3
74
, 37
7, 3
78
fin
gern
ail
is d
raw
n a
cro
ss t
he
ma
rks.
De
ep
ly in
cise
d s
cale
s sh
ow
an
ob
vio
us
text
ure
wh
en
a fi
nge
rna
il is
dra
wn
acr
oss
th
e m
ark
s.
8.
no
n-G
erm
an
23
.5
0 c
m s
cale
& 3
63
, 36
4, 3
67
, 37
4, 3
77
, 37
8
(e)
Tick
s a
re t
he
sm
all
ext
en
sio
ns
to t
he
div
isio
n m
ark
s w
hic
h e
xte
nd
be
yon
d t
he
ra
ilw
ay
tra
ck li
ne
s. S
ee
als
o (a
a).
9.
36
4, 3
67
24
.5
0 c
m s
cale
& 3
60
, 36
3, 3
64
, 36
7, 3
74
, 37
7, 3
78
(f
)Id
en
tifi
cati
on
nu
mb
ers
of t
he
su
bd
ivis
ion
s o
n t
he
Ma
nn
he
im s
cale
s b
etw
ee
n t
he
ma
jor
div
isio
ns
of 1
, 2, 3
etc
. are
eit
he
r D
eci
ma
l
10
.n
ot
all
-wo
od
or
12
.5 o
r 5
0 c
m s
cale
or
36
1, 3
66
25
.5
0 c
m s
cale
& 3
54
, 35
7, 3
60
, 36
3, 3
64
, 36
7, 3
74
, 37
7, 3
78
no
tati
on
(eg
1.2
, 1.2
, 1.3
etc
) o
r N
on
-de
cim
al n
ota
tio
n (e
g 1
, 2, 3
etc
.). I
n t
he
de
cim
al n
ota
tio
n t
he
1.5
an
d 1
5 n
um
be
rs w
ere
11
.n
ot
12
.5 o
r 5
0 c
m s
cale
or
36
62
6.
35
4, 3
57
, 36
3, 3
64
, 36
7, 3
68
, 37
4, 3
77
, 38
0in
itia
lly
dis
pla
ced
on
th
e A
an
d B
sca
les
com
pa
red
to
th
e r
est
of t
he
su
bd
ivis
ion
nu
mb
ers
. Se
e a
lso
(aa
).
12
.a
ll-w
oo
d2
7.
35
4, 3
57
, 36
4, 3
67
, 36
8, 3
74
, 37
7, 3
80
(g
)Id
en
tifi
cati
on
nu
mb
ers
for
the
div
isio
ns
on
th
e M
an
nh
eim
sca
les
we
re in
itia
lly
pri
nte
d b
y h
an
d o
ne
dig
it a
t a
tim
e a
nd
13
.n
ot
all
-wo
od
or
12
.5 o
r 5
0 c
m s
cale
or
36
62
8.
35
4, 3
57
, 36
3, 3
64
, 36
7, 3
74
, 37
7, 3
80
con
seq
ue
ntl
y sh
ow
so
me
va
ria
tio
n in
th
e a
lign
me
nt
of t
he
dig
its.
Su
bse
qu
en
tly
the
nu
mb
ers
we
re p
rin
ted
usi
ng
a t
em
pla
te
14
.n
ot
all
-wo
od
or
12
.5cm
sca
le o
r 3
61
, 36
62
9.
35
4, 3
57
, 36
4, 3
67
, 37
4, 3
77
, 38
0gi
vin
g a
mo
re u
nif
orm
ly a
lign
ed
ap
pe
ara
nce
. Se
e a
lso
(aa
)
15
.n
ot
all
-wo
od
or
12
.5 o
r 5
0 c
m s
cale
s o
r 3
61
, 36
6, 3
68
*3
69
po
ssib
le fl
at
or
reb
ate
ba
ck
(h)
Nic
kel p
late
d b
rass
an
d n
icke
l sil
ver
curs
ors
are
he
avy
an
d s
hin
y (i
f th
e p
lati
ng
ha
s n
ot
wo
rn o
ff) c
om
pa
red
to
alu
min
ium
cu
rso
rs.
Wo
rn p
late
d c
urs
ors
wil
l sh
ow
an
un
de
rlyi
ng
bra
ss c
olo
ur.
Pla
ted
cu
rso
rs a
re s
ligh
tly
ma
gne
tic,
nic
kel s
ilve
r cu
rso
rs a
re n
ot.
Ba
ck la
be
l me
da
ls t
ext
Mo
de
l nu
mb
er
lab
el (
ff)
Dig
it r
egi
ste
rin
g
Ho
ok
ind
ex
for
ed
ge lo
g-
log
sca
les
Cro
ss-s
ect
ion
(ff)
Bra
nd
te
xt o
n fr
on
t (g
g)
Ba
ck la
be
l sty
le (h
h)
'Go
ld a
nd
Fir
st-c
lass
Pri
ze M
ed
als
.'
No
bo
rde
r
Soli
d b
ord
er
'Pri
ze M
ed
als
fro
m a
ll im
po
rta
nt
… e
xhib
itio
ns.
'
'Re
che
nst
ab
…'
Sma
ll b
lock
Styl
e A
Bro
ken
bo
rde
r
Top
ed
ge
Bo
tto
m e
dge
BO
X
Re
cta
ngu
lar
Fla
tte
ne
d r
ect
an
gula
r w
ith
ro
un
de
d e
dge
s
Ba
ck la
be
l aw
ard
s
Alu
min
ium
Nic
kel s
ilve
r
Wit
h 2
mm
scr
ew
s
Wit
h 1
mm
scr
ew
s
Ro
un
de
d
Squ
are
cu
t
2 e
ach
on
left
& r
igh
t e
dge
s
'St.
Lou
is 1
90
4' e
xhib
itio
n
Wit
h 2
do
me
d r
ive
ts
Styl
e B
Styl
e C
Styl
e D
'Pa
ris
19
00
' exh
ibit
ion
Ova
l
Arc
he
d s
crip
t
Wit
h 1
do
me
d &
1 fl
at
rive
t
Wit
h 2
fla
t ri
vets
Pre
sen
t (c
en
tre
riv
ete
d)
Ad
just
ab
le g
lass
Win
do
w c
orn
ers
Ten
sio
n S
pri
ng
Fra
me
ma
teri
al (
h)
Ch
ise
l in
de
xes
CU
RSO
R (e
e)
Nic
kel p
late
d b
rass
Overview of A.W. Faber-Castell Slide Rule Dating Chronology 1892-1920
- 7 -
(aa)
Sca
le fo
rmat
s(e
e)
Cu
rso
r e
xam
ple
s
(bb
) Sl
ide
ru
le b
ack
styl
e la
be
l exa
mp
les
(cc)
Scr
ipt
M g
auge
mar
k(d
d)
Slid
e r
ule
bac
k la
be
l te
xt s
tyle
(ff)
Bo
x p
rofi
le a
nd
mo
de
l lab
el
(gg)
Bo
x b
ran
d t
ext
1. G
erm
an
2. G
erm
an
(la
rge
tex
t)
6. F
ren
ch
3. G
erm
an
(sm
allt
ext)
5. E
ngl
ish
(sm
all t
ext
)
7. E
ngl
ish
Ele
ctro
8. N
on
-En
glis
h El
ect
ro
Ad
vert
isin
g
In/c
mco
nve
rsio
n sc
ale
4. E
ngl
ish
(lar
ge t
ext
)
A. W
ith
ta
ilsB
.Wit
ho
ut
tails
Pla
in s
cale
s, d
ecim
al n
ota
tion
, han
d
pri
nte
d n
umb
ers
type
face
A, d
ispl
ace
d 1
.5
Do
ub
le li
ne
railw
ay t
rack
sca
les,
tic
ks, n
on-
de
cim
al n
ota
tio
n, t
emp
late
pri
nte
d n
um
ber
s ty
pe
face
B, a
rro
w ±
sym
bol
s
Sin
gle
lin
e ra
ilway
tra
ck s
cale
s, t
icks
, no
n-d
eci
mal
no
tati
on
, tem
pla
te p
rin
ted
nu
mb
ers
typ
efa
ce C
, arr
ow
±sy
mb
ols
Un
eq
ua
l dou
ble
line
railw
ay t
rack
sca
les,
no
tic
ks, d
ecim
al n
ota
tion
, ha
nd p
rin
ted
nu
mb
ers
typ
efa
ce A
, dis
pla
ced
1.5
Squ
are
bo
x, la
bel
wit
h n
ob
ord
er
Squ
are
bo
x, la
bel
wit
h b
roke
n b
ord
er
Fla
t b
ox
wit
h r
oun
ded
ed
ges
Ova
l bo
x, la
bel
wit
h so
lid
bo
rde
r
Nic
kelp
late
d b
rass
, ch
isel
s, 2
m
m a
dju
stin
g sc
rew
s, r
oun
ded
win
do
w, n
o s
pri
ng
Alu
min
ium
, dig
it r
egis
teri
ng w
ith
2
do
me
d r
ivet
s, r
oun
ded
win
do
w,
cen
tre
riv
ete
d sp
ring
Alu
min
ium
,ho
ok in
dex,
sq
ua
re c
ut
win
dow
, ce
ntr
e r
ive
ted
spri
ng
Arc
he
d s
cip
t'R
ech
en
stab
...'
Sma
ll b
lock
A. E
ngl
ish
(go
ld o
n b
lack
)
B. E
ngl
ish
(go
ld o
n b
lack
or
bla
ck o
n w
hite
)
C. E
ngl
ish
(re
d &
gre
ente
xt)
C. N
on
-En
glis
h (g
ree
n &
red
tex
t)
D. E
ngl
ish
(wit
h c
are
inst
ruci
ons)
D. N
on
-En
glis
h (w
ith
care
inst
ruci
ons
)
(hh
) B
ox
bac
k la
be
l sty
le e
xam
ple
s