In the five adjacent counties there occur 110 species of flowering plants unknown in Hertfordshire. On the other hand, Hertfordshire has about a dozen plants (exclusive of varieties of the bramble) unknown in the adjacent counties. Of the 893 native flowering plants of Hertfordshire about 110 have not been recorded from Cambridgeshire, while about 120 are wanting in Bedfordshire, 170 in Buckinghamshire, 140 in Middlesex, and 100 in Essex. These figures may, however, be subject to considerable modification by future research. The following passage on the relations of the Hertfordshire flora is quoted from the _Victoria History of the Counties of England_:-- “Taking the number of species in any adjoining county which are absent from Hertfordshire as the best index of the degree of relationship, it would appear that the flora of Bucks is the most nearly allied to that of Herts, and that those of Cambridge and Essex are the most divergent.... This is just what might be expected from the physical features and geological structure of these counties. The floras of Cambridge and Essex have also a more northern or north-eastern facies [character] than that of Hertfordshire, which is of a decidedly southern type. The large number of Hertfordshire species which have not yet been recorded from Buckinghamshire is probably due to the flora of that county not having been so thoroughly investigated as ours has been.” 8. Climate and Rainfall. In its original sense the word climate meant the degree of inclination of the sun’s rays at any particular spot at a specified date; but nowadays it is employed to designate the average type of weather experienced in a district. In this latter sense it comprises the results of the combined effects of temperature, atmospheric pressure, the degree of moisture in the air, the direction and force of the wind, and the amount of rainfall; the study of climate constituting the science of meteorology. Although the climate of the British Isles is of an exceedingly changeable type, yet the average of the seasonal changes is far from being the same in all parts of the country. Taking temperature alone, we find, for instance, that while the average for the whole year in Shetland is as low as 43° Fahrenheit, in the Scilly Islands it rises to 53°. It is a very general idea that in our islands the winter temperature of a place depends upon whether it is situated in the north or the south. This, however, is a mistake, the temperature having little relation to latitude, but growing colder as we pass from the west to the eastern side of the country; the south of England, as a whole, being milder than the north, not because it is the south, but because it includes such a large extent of land in the west. The degree of elevation above the sea-level has much to do with temperature and the amount of moisture in the air; high lands being, as a rule, colder and drier in winter than those lying at lower levels. On account