Februaey 1, 1895.] 



KNOWLEDGE. 



29 



nights, and, iii fact, the natives say they do not come out 

 at all in stormy weather or on very dark nights. They 

 live on berries and fruits, being specially fond of the palm 

 oil-nut, which they take to their nests to peel and eat. 

 They pass from tree to tree with great rapidity, usually 

 choosing to jump from a higher branch to a lower one, 

 and then climbing up the tree to make a fresh start. 

 The temperature on the hills varies considerably. During 

 the time I was there — the rainy season, from the middle of 

 April to the middle of .June — it was never very hot, one 

 night the thermometer going down to 44^ on the ground. 

 Of course, in the dry season it is much hotter, but the 

 natives say these animals are much more plentiful in the 

 rains, and that the rainier the season the more they see. 

 They litter twice a year, once about September, the young 

 remaining in the nest for about nine weeks, durmg which 

 they are fed by the old ones on such food as shoots and 

 kernels; they do not attempt to jump till the end of that 

 period, extending the length of their jumps with their 

 growth. I do not know the other time of breeding, or 

 whether they have a regular season. The hunters told me 

 that two or three were usually born at one birth, and never 

 more than four." 



Within the last few years an extraordinary number of 

 new mammals have been discovered in Africa, some of the 

 best known and most generally interesting being several 

 large antelopes from Somaliland. To the naturalist, 

 however, a tiny little creature like the one under con- 

 sideration, which represents a totally new type, is of far 

 more interest than any antelope, whether the latter indicate 

 a new genus or merely a new species. In Eastern Africa 

 German and English zoologists and collectors are rivalling 

 one another in the zeal with which new or rare forms are 

 brought to light, but on the West Coast our German cousins 

 seem to be having it all their own way. Although we 

 should be the last to envy them the discovery of this latest 

 addition to the mammalian fauna of West Africa, we cannot 

 help expressing a hope that our own countrymen will not 

 allow themselves to be outstripped in the race of discovery 

 and collecting. 



AUTOMATIC STABILITY IN AERIAL VESSELS. 



By Thomas Moy. 



THE importance of securing longitudinal stability — 

 which means travelling on an even keel — does not 

 readily suggest itself to those who have not studied 

 this problem. To render the subject familiar: 

 suppose a wagonette full of people to be travelling 

 on an ordinary road, and the hind wheels to suddenly 

 collapse, the passengers would slide downwards to the 

 hinder part, one upon another. The same result would 

 accrue if the vehicle came to a soft place in the road. 

 Or suppose a river steamer suddenly went down by the 

 head, and the stern rose up out of the water. In each 

 case longitudinal stability would be lost. Fortunately, 

 these are very imlikely occurrences on land and water ; but 

 in the air, and especially with elongated gas bags or 

 aerostats, such uncomfortable " tiltings " frequently happen. 

 It therefore becomes very important that the man at the 

 helm of an aerial vessel should he entirely relieved of 

 anxiety as to its horizontal position, and be enabled to 

 concentrate his attention upon the course to be steered, 

 with as much confidence as if he steered an ordinary river 

 steamer. 



Turning a carriage to the right or left upon an ordinary 

 road, or steering a vessel to starboard or port on water, is 

 such a very simple operation, that one is apt to overlook the 



fact that, in submarine and aerial navigation, the main 

 support is wanting ; the road or the water level is not there, 

 and their absence must be provided for. It is an absolute 

 necessity that such vessels should be capable of automati- 

 cally assuming and maintaining the predetermined position, 

 whether perfectly horizontal or slightly inclined. This 

 cannot be carried out by hand. No steersman in charge 

 of the tiller of a horizontal rudder or tail could keep a 

 vessel in the desired position. High speed is most essen- 

 tial to the accomplishment of mechanical flight, and no 

 regular high speed can be secured if the vessel and its 

 carefully arranged planes are continually varying their 

 angle relatively to the course to be travelled. 



Recognizing the importancs of these facts, I invented 

 and patented plans for securing automatic horizontal 

 stability, in the year 1891, the patent being No. 14,742 of 

 that year. Two methods of carrying out the invention are 

 shown in the specifioition, and I now propose to describe 

 and explain the simpler of the two methods. 



A great many patents have been filed in which the 

 ordinary pendulum has been described, a? applied to this 

 purpose. Bat it will readily be understood that, with a 

 vessel going at a high speed, the po-;vor of the mere 



FIQ.I 



^¥^ 





hanging pendulum is very weak, and it would require a 

 very great departure of the vessel from its true course to 

 bring the power of the pendulum to bear upon the hori- 

 zontal rudder. This difficulty I overcame — first, by 

 using an inverteil pendulum, with limited motion ; and 

 secondly, by using the position of the pendulum in 

 applying an independejit force to the correction of any 

 departure from the desired position of the vessel, relatively 

 to its course. 



Referring to Fig. 1, 3 is a transverse horizontal shaft, 

 projecting outwards on each side of the stern portion of 

 the vessel, to port and starboard, the outer ends being 

 fitted with horizontal planes for steering. 4 is the tiller, 

 the outer end passing through the vertical guide 5, and 

 entering the slot G in the rack 7, as also shown in Fig. 2. 

 In the position shown, the tiller and the steering planes or 

 rudders are supposed to be in a perfectly horizontal position. 

 8 is a shaft, formed in two parts, jointed at 9, and fitted 

 with a pinion at 10. The pinion is bored out to receive a 

 ball, fitted to the end of the arm 13. The shaft 8 is kept 

 constantly rotating in one direction by any means, such 

 as clockwork, or by a connection with the necessary 

 machinery carried on board, or by a treadle worked by 

 the foot ; very little power being requured to turn the 

 shaft. 



The rack 7 is capable of sliding horizontally in guides, 

 the arms 20 being extended for that purpose ; and the 

 pinion 10 and tiller 4 are guided vertically in the guide 5. 



The inverted pendulum is pivoted at 12. The arms 13 



