37); the opposed faces of these plugs are perfectly smooth, and are placed within a millimetre of each other.
As a rule flies are of small or moderate size, and many, such as certain blood-sucking midges of the genus Ceratopogon, are even minute; as extremes of size may be mentioned a common British midge, Ceratopogon varius, the female of which measures only 14 millimetre, and the gigantic Mydaidae of Central and South America as well as certain Australian robber-flies, which have a body 1-11n.
They range from a millimetre or so (smaller species of Aeolosoma) to 6 ft.
In a well-made apparatus the pressure in the exhausted vessel is now reduced to I t o or 2 1, of a millimetre, or even less.
Referring the reader to the article Elasticity for the theoretical and to the Strength Of Materials far the practical aspects of this subject, we give here a table of the "modulus of elasticity," E (column 2), for millimetre and kilogramme.
The general nature of the phenomena is thus easily understood; but it is at a maximum at pressures comparable with a millimetre of mercury, at which the free path is still small, the greater number of molecules operating in intensifying the result.
The relieving force that marched into Kumasi consisted of moo fighting men (all West Africans), with 60 white officers and non-commissioned officers, two 75-millimetre guns, four seven-pounder guns and six Maxims.
It has been found that the " carbons " in drills can safely be subjected to a pressure of over 60 kilograms per square millimetre, and a speed of 25 metres per second.
With a period of 18 seconds, and the record-receiving paper at a distance of about 15 ft., a deflection of I millimetre of the light spot may indicate a tilting of AD part of a second of arc, or I in.
The value in terms of arc of the scale of the record can be obtained by measuring the distance between the magnet mirror and the recording drum, and in most observations it is such that a millimetre on the record represents one minute of arc. The time scale ordinarily employed is 15 mm.
For example, if the diameter be one millimetre, the disturbance is multiplied 1000 fold in about one-fortieth of a second.
The earth would intercept an amount of it proportional to the solid angle it subtends at the sun; that is to say, it would receive a deposit of meteoric matter about one-tenth of a millimetre, of density say 2, over its whole surface in the course of the year.
The metre and the kilometre, for instance, or the metre and the millimetre, are not directly comparable; but the metre can be conceived as containing too centimetres.