Fig. 81.—Stanley's Engineer's level.
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The reviser has also patented a new form of spherical joint, which has met with equal favour. This improvement consists of a section of a ball (screwed to fit the stand head) fitted within the lower plate and a simple means of clamping it in any position, which, when released allows of sufficient rocking movement in any direction to compensate for any uneven setting up of the stand. It does not add to the height of the instrument, may be instantly set nearly level, and less than half a turn of the levelling screws will bring the instrument into true position. It is shown fitted to the new engineer's level at Fig. 82 below, but is equally applicable to any other form of instrument.
Fig. 82.—Stanley's Engineer's level fitted with quick setting spherical lower plate.
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As ninety per cent. of the orders now for levels are for the form shown at Fig. 82, the reviser ventures to think that this must be favoured by the profession as the best practical instrument yet made.
A further improvement has been made by making the diaphragms interchangeable, so that any form of diaphragm that is preferred may be instantly fitted without disturbing the adjustment, and when lines on glass are used it may be removed for cleaning, and replaced without interfering with the adjustment.
The diaphragms illustrated below, Fig. 83, are usual forms, and it is recommended that when webs are preferred a glass one should be carried as a spare in case of accidents.
