6.1

The scale spacing must be at least for solid-stem thermometers and at least for enclosed-scale thermometers.

6.2

Graduation lines must be uniform and clear, and must be engraved or printed clearly and indelibly.

The graduation lines must be perpendicular to the axis of the thermometer. Their thickness must not be more than one-fifth of the length of a scale division for enclosed-scale thermometers, or one quarter of the length of a scale division for solid-stem thermometers. The half-degree and degree lines must be longer than the other lines.

6.3

The lines corresponding to degrees must be numbered ; these numbers must be engraved or indelibly printed.

For solid-stem thermometers, the numbering of the line corresponding to is optional and may be replaced by the special form of marking specified in 6.4.

6.4

Only the line corresponding to the temperature of may be indicated specially, using a different color from that of the numbers and/or by additional marking such as a dot, asterisk or arrow.