'real' strange problem in 7.1.3

I have a database in PG 7.1.3 with the following schema:

db02=# \d ellipse
Table "ellipse"
Attribute | Type | Modifier
--------------------------+--------------+----------
subject | text |
arm | character(1) |
rep | integer |
exp_date | date |
exp_time | time |
success | integer |
figure_radius | integer |
tube_radius | integer |
cursor_radius | integer |
direction | integer |
ellipse_ratio | real |
exag_ratio | real |
exag_start | integer |
exag_end | integer |
rotation_angle | real |
min_inter_trial_interval | integer |
Index: pkellipse

If I try the command:
db02=# select distinct arm from ellipse where exag_ratio = 1.0;
arm
-----
L
R
(2 rows)

which is correct.

Now I try the same command with a different 'real' field:
db02=# select distinct arm from ellipse where ellipse_ratio = 1.8;
arm
-----
(0 rows)

BUT, if I put the value in quotes (as if it were a string), I get:

db02=# select distinct arm from ellipse where ellipse_ratio = '1.8';
arm
-----
L
R
(2 rows)

which is correct.

This variable ellipse_ratio seems to be the only one of type 'real'
that requires me to use quotes (which doesn't really make sense since
it's not a character or string anyway). exag_ratio and rotation_angle
behave as I would expect a real-typed variable to behave.

db02=# select distinct exag_ratio, ellipse_ratio, rotation_angle from
ellipse;
exag_ratio | ellipse_ratio | rotation_angle
------------+---------------+----------------
1 | 0.56 | 0
1 | 1.8 | 0
(2 rows)

Has anyone seen this behavior before? Perhaps, I'm doing something
wrong here or thinking of this all wrong?

Thanks.
-Tony Reina

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db02=# select version();
version
-------------------------------------------------------------
PostgreSQL 7.1.3 on i686-pc-linux-gnu, compiled by GCC 2.96
(1 row)

PG server is RH Linux 7.1 (Seawolf), PIII 400 MHz
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