of the comparatively high elevation of a considerable proportion of its area and its easterly position, coupled with the prevalence of north-easterly and easterly winds in spring, Hertfordshire ought to have, on the whole, a cold and bracing climate for the greater part of the year; and, as a matter of fact, such is the case. Indeed, it is commonly said that northern Hertfordshire is so cold and bracing, that only strong and robust constitutions can stand it; but that for those blessed with such constitutions it is one of the healthiest counties in the kingdom. Hertfordshire, however, like England on a small scale, has local climates of its own, dependent upon differences in elevation above the sea-level, in the amount of rainfall, in the nature of the geological formation and soil, and also in aspect, especially as regards protection from the east wind in spring. The slope of a hill facing south or south-west receives for instance far more sun in winter than one which looks in the opposite direction; while it also escapes the full blast of the bitter east wind. Places situated on chalk, and above all on gravel, are drier, and consequently--if on the same level and with a similar aspect--also warmer than those on cold, heavy clay or marl. As if to confirm and perpetuate the above-mentioned popular error, it happens that the northern and north-western districts of the county, that is to say, those constituting the chalk area, are very much colder and more bracing than those to the south and east, whose substratum is clay. This difference depends, however, not on differences of latitude, but on the lower elevation of the southern as compared with the northern districts, coupled with the protection from cold winds afforded to the low lands by the high ground. To those who are in the habit of travelling by the Midland railway from the north-western corner of the county to London, the differences between the climate of the northern and the southern districts is made self-apparent in early spring by the extraordinary difference in the condition of the hedges and trees on the two sides of the Elstree tunnel. It is true that on this particular route the district south of the tunnel is in Middlesex, but to the eastward much of the lowland is in Herts. On the northern side of the range of chalk-hills pierced by this tunnel the hawthorn hedges may be seen at a certain period of the spring to be absolutely devoid of a sign of green; while on the opposite side they will be in full leaf. There is, in fact, about a fortnight’s difference between the Elstree and the Mill Hill side of this range in regard to the development of spring-vegetation; and while the northern side is exposed to the full force of the east wind, the combes and valleys with a south-westerly aspect near the summit of the opposite flank are so warm and sheltered that hardy species of bamboo and palm will grow in the open air almost as luxuriantly as in similar situations in Surrey