Walking the other day in an old hemlock wood, I counted over forty varieties of these summer visitants, many of them common to other woods in the vicinity, but quite a number peculiar to these ancient solitudes, and not a few that are rare in any locality. It is quite unusual to find so large a number abiding in one forest,--and that not a large one,--most of them nesting and spending the summer there. Many of those I observed commonly pass this season much farther north. But the geographical distribution of birds is rather a climatical one. The same temperature, though under different parallels, usually attracts the same birds; difference in altitude being equivalent to the difference in latitude. A given height above the sea level under the parallel of 30 deg. may have the same climate as places under that of 35 deg., and similar Flora and Fauna. At the head-waters of the Delaware, where I write, the latitude is that of Boston, but the region has a much greater elevation, and hence a climate that compares better with the northern part of the State and of New England. Half a day's drive to the southeast brings me down into quite a different temperature, with an older geological formation, different forest timber, and different birds,--even with different mammals. Neither the little Gray Rabbit nor the little Gray Fox is found in my locality, but the great Northern Hare and the Red Fox are seen here. In the last century a colony of beavers dwelt here, though the oldest inhabitant cannot now point to even the traditional site of their dams. The ancient hemlocks, whither I propose to take the reader, are rich in many things beside birds. Indeed, their wealth in this respect is owing mainly, no doubt, to their rank vegetable growths, their fruitful swamps, and their dark, sheltered retreats. Their history is of an heroic cast. Ravished and torn by the tanner in his thirst for bark, preyed upon by the lumberman, assaulted and beaten back by the settler, still their spirit has never been broken, their energies never paralyzed. Not many years ago a public highway passed through them, but it was at no time a tolerable road; trees fell across it, mud and limbs choked it up, till finally travellers took the hint and went around; and now, walking along its deserted course, I see only the footprints of coons, foxes, and squirrels. Nature loves such woods, and places her own seal upon them. Here she shows me what can be done with ferns and mosses and lichens. The soil is marrowy and full of innumerable forests. Standing in these fragrant aisles, I feel the strength of the vegetable kingdom and am awed by the deep and inscrutable processes of life going on so silently about me.