Later experimenters in this direction were Kress, a German; Professor Wellner, an Austrian; and W. R. Kimball, an American. Kress, like most Germans, set to the development of an idea which others had originated; he followed de la Landelle and Forlanini by fitting two superposed propellers revolving in opposite directions, and with this machine he achieved good results as regards horse-power to weight; Kimball, it appears, did not get beyond the rubber-driven model stage, and any success he may have achieved was modified by the theory enunciated by Berriman and quoted above. The habit of the family at this time, while spending the main part of the year at Portland Place, was to go to some country place in the summer, for several weeks, sometimes renting a house where they could stay all together, sometimes breaking into smaller parties. In 1846 they were at Herne Bay; in 1847 at Gresford; in 1848 at Dover and Walmer. While at Walmer they were a good deal thrown with the Duke of Wellington, and the former acquaintanceship ripened into more of intimacy. Before deciding on Walmer, two or three of the party went to Dover, and they had a somewhat perilous voyage thither, to which the following letter makes allusion:鈥? 鈥楴ow we will go on with the rest of the shorthand,鈥?he said. The 鈥楽ilver Queen鈥?and its crew. 无码av高清毛片在线看_日本一级特黄大片_日本毛片免费视频观看_ It was altogether a very jolly life that I led in Ireland. I was always moving about, and soon found myself to be in pecuniary circumstances which were opulent in comparison with those of my past life. The Irish people did not murder me, nor did they even break my head. I soon found them to be good-humoured, clever 鈥?the working classes very much more intelligent than those of England 鈥?economical, and hospitable. We hear much of their spendthrift nature; but extravagance is not the nature of an Irishman. He will count the shillings in a pound much more accurately than an Englishman, and will with much more certainty get twelve pennyworth from each. But they are perverse, irrational, and but little bound by the love of truth. I lived for many years among them 鈥?not finally leaving the country until 1859, and I had the means of studying their character. 鈥業n continuing the general principles of aerial navigation, for the practice of the art, many mechanical difficulties present themselves which require a considerable course of skilfully applied experiments before they can be overcome; but, to a certain extent, the air has already been made navigable, and no one who has seen the steadiness with which weights to the amount of ten stone (including four stone, the weight of the machine) hover in the air can doubt of the ultimate accomplishment of this object.鈥? Only extracts from the translation of Lana鈥檚 work can be given here, but sufficient can be given to show fully the means by which he designed to achieve the conquest of the air. He begins by mention of the celebrated pigeon of Archytas the Philosopher, and advances one or two theories with regard to the way in which this mechanical bird was constructed, and then he recites, apparently with full belief in it, the fable of Regiomontanus and the eagle that he is said to have constructed to accompany Charles V. on his entry into Nuremberg. In fact, Lana starts his work with a study of the pioneers of mechanical flying up to his own time, and then outlines his own devices for the construction of mechanical birds before proceeding to detail the construction of the aerial ship. Concerning primary experiments for this he says:鈥?