June 12, 1891.] 



SCIENCE. 



331 



between the two boundaries, and the whole coast-line being about 

 a thousand kilometres in length. The whole of this wide expanse 

 is threatened by ruin, ruin compared to which the ravages of the 

 phylloxera are mild. The last news which we had from the 

 western province was that around Tlemgen, on the frontier, flights 

 of locusts were alightihg unintermittently, and that a caravan 

 just arrived there from Morocco had travelled for thirty-two days 

 in the midst of locusts, the country being entirely devastated. I 

 have said enough to show how the central department of Algiers 

 is threatened, and now on the borders of Tunisia, advancing from 

 the east, we had met once more with the dread hordes. The night 

 before our arrival at Bone, the frontier port, a train coming thither 

 from Tunis had been actually blocked for half an hour by a swarm 

 at a little place called Oued-Zerga, and in the capital of the Beys 

 the natives were trying to make the best of the plague by cooking 

 and selling the sauterelles for food. 



I have not the space, even if I had the technical knowledge, to 

 describe the means by which Algerian cultivators are trying to stay 

 the pest; how they set about the unpleasant work of destroying 

 the eggs, and how, after incubation, they devise methods for 

 stopping the march of the criquets, which, if unchecked, literally 

 eat their way along, leaving the most verdant aad fertile tracts a 

 brown wilderness. Suffice it to say, that not only are the local 

 authorities, the maires, and sous-prefets, organizing resistance and 

 raising subsidies for the struggle, but, what is moi'e significant 

 in a territory which is above all things a military training-ground 

 for France, the general commanding the forces in Algeria has 

 granted a remission of thirteen days to all cultivators called to 

 serve with the colors, whose properties are menaced by the lo- 

 custs. 



My last glimpse of the country, which I have the greatest reason 

 for loving that a woman can have, was across the vineyards whose 

 leafy lines stretch in never-ending vistas over the rich plains by 

 the Tunisian frontier,- and I thought of the sinister Arab prophe- 

 cies which foretold that, after the conquest by the Franks of this 

 fair land, an army of invaders, worse even than they, should come 

 up from the desert, and extend the boundaries of the Sahara to 

 the shores of the Blediterranean. 



apart, the Ohio experiments show better results from the six-inch 

 planting. 



Such close planting as this causes the ears to be chiefly nubbins, 

 and therefore it is not to be recommended when merchantable 

 grain is the product desired ; but for silage purposes it is not ne- 

 cessary that the grain should be merchantable. 



VARIETY AND PLANTING OF CORN. 



Bulletin No. 15 of the Pennsylvania Agricultural Experiment 

 Station is a report of experiments on the influence of variety and 

 the rate of seeding on the yield of ensilage corn. Two varieties 

 of com were planted, one the field corn ordinarily grown in that 

 locality, the other Breck's Boston market ensilage, a large-grow- 

 ing variety which barely reaches the glazing stage before frost in 

 that locality. Both varieties were sown in duplicate plots, of two 

 rates of seeding each, the plots being alternated. The rows were 

 three and a halt feet apart, with guard rows between the plots, 

 so that the ground was all equally occupied. Manure was applied 

 liberally, but by a mistake the thick-seeded plots received larger 

 quantities of manure as well as of seed. The thin-seeded plots 

 were planted so that the stalks stood fourteen inches apart in the 

 rows, while on the thick-seeded plots the stalks were three and a 

 half inches apart. 



The average yield of each pair of plots, calculated to one acre, 

 was: small, thin-seeded, 11,962 pounds; small, thick-seeded, 19,- 

 013 pounds; large, thin-seeded, 30,9.55 pounds; large, thick-seeded, 

 36.840 pounds. It appears, therefore, that the larger variety gave 

 a decidedly larger yield than the smaller one, and that thick seed- 

 ing was decidedly more profitable than thin seeding. 



Chemical analyses were made of samples from the various plots, 

 from which it appeared that the produce of the larger variety and 

 of the thicker seeding showed even greater superiority than that 

 indicated by the gross yield. 



Experiments similar to the foregoing have been conducted at 

 the Ohio Experiment Station over several seasons, and these have 

 uniformly showed a larger yield, both of grain and fodder, and 

 therefore of food for animals, when the corn was so planted that 

 the stalks stood about six inches apart in rows about three and a 

 half feet apart, than when the distance between the stalks was 

 greater. As between planting six inches apart and thi'ee inches 



THE TRANSANDINE RAILWAY. 



The Transandine Railway now in process of construction across 

 the Andes Mountains, for the purpose of connecting the railway 

 systems of Chili and the Argentine Republic, is an enterprise in- 

 volving many engineering difficulties. London Engineering has 

 devoted considerable space to a series of illustrated articles on the 

 railway and its construction, from which we gather the following 

 facts. 



The length of the new railway is 149 miles, of which 109 miles 

 are on Argentine territory, starting from the city of Mendoza, 

 which is 2,376 feet above the sea. In Chili there are forty miles, 

 connecting with the Chilian system at Santa Rosa, 2,704 feet above 

 sea-level. The greatest height attained by the railway is 10,460 

 feet above sea-level, the tunnel at that point being some two 

 thousand feet below the summit of the mountains. There are 

 eight tunnels grouped near the summit, aggregating 9.33 miles in 

 length, the longest, the summit tunnel, having a length of 5,540 

 yards. To overcome a part of the difference in level within a 

 short distance, and at suitable working gradients, it has been found 

 necessary to construct a spiral tunnel 2,061 yards long, with a 

 radius of 200 metres and a grade of eight feet in a hundred. It 

 may be added that this grade is maintained through the whole 

 nine miles of tunnelling, except, of course, in the summit tunnel. 



It is in the boring of these tunnels that the greatest engineering 

 difficulties are encountered. The absence of fuel, and the enor- 

 mous expense of obtaining it, put steam out of the question as a 

 motive power for driving the air compressors, — air-actuated drills 

 being the means employed for boring the tunnels. Water power, 

 the only other means available, was to be had, but at a considera- 

 ble distance from the work. It was therefore decided to use the 

 water-power for driving electro-dynamos, transmit the electric 

 current by copper conductors to the sites selected for the com- 

 pressors, convert it into power by means of electro-motors, thereby 

 actuating the compressors and furnishing compressed air for the 

 drills. The installations for this purpose are unique, as it is 

 probably the first time that the power for compressing air for drills 

 has been conveyed such a distance by electric cables. There are 

 three installations, one upon the Argentine and two on the Chilian 

 side of the Andes, each being distinct in all points, except that the 

 primary stations on the Chilian side are both located at one place. 

 Each installation has a primary station, where the turbines and 

 dynamos are situated, and a secondary station, with electro-motors 

 and air compressors. 



The Chilian installation consists of two primary stations under 

 one roof at Juncal, with secondary stations at Juncalillo and Cala- 

 vera, and separate cables for transmitting the current. The power 

 for driving the turbines is obtained from the Quebrada Juncalillo, 

 the water being conveyed to the turbines, a distance of 1,420 yards, 

 by a double line of steel pipes. The primary station at Juncal for 

 the Juncalillo station consists of six Girard turbines, each giving 

 80 horse-power, a total of 480 horse-power. Each 80 horse-power 

 turbine is coupled directly to the shaft of an 80 horse-power dy- 

 namo, consequently there will be no loss of power in transmission 

 from the turbines to the dynamos. The latter are grouped in two 

 groups of three dynamos each, each group having a main and 

 return transmission cable. A great advantage is gained in having 

 two groups, as should accidents or other cause prevent one from 

 being worked, the whole of the tunnelling would not be stopped. 

 At the secondary station at Juncalillo, about 3,281 yards from Jun- 

 cal, the power available is 401. 8 horse-power, cables being attached 

 to six electric motors, similar to the 80 horse-power dynamos, 

 which drive six air compressors, 



The Juncal-Calavera installation is very similar to the one de- 

 scribed above. The turbines are in the same shed, and take their 

 water from the same source. These and the dynamos are also of 



