# How to use *Base line* in a sentence

The year 1784 marks the beginning of the ordnance survey, for in that year Major-General Roy measured a

**base line**of 27,404 ft.In 1784 the base-line of the first trigonometrical survey in England was laid down on the heath.

The light reflected from the fixed mirror traces a straight line on the paper, serving as a

**base line**from which the variations in declination are measured.As the declination changes the spot of light reflected from the magnet mirror moves parallel to the axis of the recording drum, and hence the distance between the line traced by this spot and the

**base line**gives, for any instant, on an arbitrary scale the difference between the declination and a constant angle, namely, the declination corresponding to the**base line**.The magnet is so weighted that its axis is approximately horizontal, and any change in the inclination of the axis is observed by means of an attached mirror, a second mirror fixed to the stand serving to give a

**base line**for the records, which are obtained in the same way as in the case of the declination.AdvertisementIf we place the base of the filament in each case on a

**base line**in the order of the successive times of observation recorded, and at distances apart proportional to the intervals of time (8.30, 10.0, 10.30, 11.40, and so on) and erect the straightened-out filaments, the proportional length of each of which is here given for each period, a line joining the tips of the filaments gives the curve of growth.The distributions of stress on the

**base line**of the model for " reservoir empty " and " reservoir full " are shown in fig.It has been already mentioned that the

**base line**of Attica is formed by the chain of Cithaeron and Parnes, running from west to east; and that from this transverse chains run southward, dividing Attica into a succession of plains.In other forms of broken pediment, the

**base line**might be interrupted.In order to adapt this formula to logarithms, we introduce a subsidiary angle p, such that cot p = cot l cos t; we then have cos D = sin 1 cos( - p) I sin p. In the above formulae our earth is assumed to be a sphere, but when calculating and reducing to the sea-level, a base-line, or the side of a primary triangulation, account must be taken of the spheroidal shape of the earth and of the elevation above the sealevel.

AdvertisementThe error due to the neglect of the former would at most amount to 1%, while a reduction to the mean level of the sea necessitates but a trifling reduction, amounting, in the case of a base-line 300,000 metres in length, measured on a plateau of 3700 metres (12,000 ft.) in height, to 57 metres only.

The measurements of a polygonal field or other area are usually taken as in § 25 (ii); a diagonal AE is taken as the base-line, and for the points B, C, D,..

It became the base-line of almost any rugged outdoor uniform.