Following the first chart of lines of equal variation compiled by Edmund Halley in 1700, charts of similar type have been published from time to time embodying recent observations and corrected for the secular change, thus providing seamen with values of the variation accurate to about 30' of arc. Possessing these data, it is easy to ascertain by observation the effects of the iron in a ship in disturbing the compass, and it will be found for the most part in every vessel that the needle is deflected from the magnetic meridian by a horizontal angle called the deviation of the compass; in some directions of the ship's head adding to the known variation of the place, in other directions subtracting from it.
Hydroxylic oxygen is obtained by subtracting the molecular refractions of acetic acid and acetaldehyde.
The latent heat L (formula 9) is found by subtracting from H (equation 15) the values of the heat of the liquid h given in the same article.
In Subtracting From The Left, We Look Ahead To See Whether A I In Any Denomination Must Be Reserved For Changing; Thus In Subtracting 274 From 637 We Should Put Down 2 From 6 As 3, Not As 4, And 7 From 3 As 6.
Starting from the dividend, we in theory keep on subtracting the unit, and count the number of subtractions that have to be performed until nothing is left.