DISCOVERY 



209 



It was by means of this apparatus used as a trans- 

 mitter that wireless telephone messages were sent 

 across the Atlantic for the first time from Arlington, 

 near Washington, to Paris in 1915, and very early in the 

 war it was used as a receiver by the French to intercept, 

 by earth-conduction, messages sent on field telegraph 

 and telephone lines, a practice which both the Germans 

 and ourselves quickly followed. At the time, great 

 surprise was expressed in this country at the intimate 

 knowledge which the enemy had of our intended 

 dispositions in the front line, and a similar surprise 

 at our knowledge was no doubt just as prevalent in 

 Germany. It was not long, however, before both sides 

 had adopted means of sending messages along the 

 wires in such a way as to make interception by the 

 opposing side almost impossible ; but there can be no 

 doubt that the first practical use of the Three Electrode 

 Valve, which has so increased the possibilities of com- 

 munication, involved both the saving and the losing of 

 many gallant Uves. 



Owing to its magnifying power, the Three Electrode 

 Valve can be used for operating high-speed recording 

 devices ; and by using automatic high-speed transmitters, 

 the rate of signalling can be very greatly increased. 

 The greatest speed that can be attained by land trans- 

 mission and aural reception is about thirty words a 

 minute, and twenty words a minute is considered to be 

 a good working speed. By automatic transmission 

 and reception, using the Three Electrode Valve, a 

 working speed of 100 words a minute is even now quite 

 practicable, and much higher speeds have been experi- 

 mentally obtained. In fact, it is in this direction that 

 wireless working may show to advantage compared with 

 long-distance submarine cable working in the near future, 

 as such very high speeds are not practicable for the 

 latter. Wireless working, however, whether by tele- 

 graph or telephone, is greatly handicapped, as compared 

 with Hne working, by the fact that it is so liable to be 

 interfered with, or " jammed, "by other wireless signalling 

 or by electrical atmospheric disturbances. Recently 

 much has been done to lessen this very serious draw- 

 back, but it still remains the great bugbear of wireless 

 communication. 



Note. — An excellent technical account of this subject is 

 given in Wireless Telegraphy and Telephony. By H. M. 

 Dowsett. (Wireless Press, gs.) 



BOOKS OF REFERENXE OX HEREDITY 



1st Section . L. Doncaster, Cytology. (Cambridge University 



Press, 1920, 21S.) 

 and Section : R. C. Punnett, Mendelism. (Macmillan, 1919, 



7s. 6i. net.) 

 3rd Section : T. H. Morgan. The Physical Basis of Heredity. 



(Lippincott, 1919, 10s. 6(i.) 



Abraham Lincoln as now 

 Known to Us 



By Lord Gharnwood 



We must consider first the national struggle in which 

 Lincoln bore the most famous part. Soon after the 

 United States had obtained independence, the slave 

 trade was abolished, and the more northern States 

 abolished slavery within their limits. Farther south 

 the movement in favour of emancipation was checked 

 by economic causes. By the Constitution, slavery was 

 a question for each State to settle for itself. Conflict, 

 however, arose about it in new States and in the 

 territories governed by the United States as a whole. 

 A compromise called the " Missouri Compromise" was 

 effected in 1820 by an Act which made slavery unlawful 

 in existing territories north of a certain line. Economic 

 pressure, however, created in the South a desire to 

 acquire new territory in which cultivation by slave 

 labour could flourish ; fanatical belief in the merits 

 of slavery took possession of the South ; there was 

 some desire to re-establish the slave trade ; Southern 

 traders aspired, encouraged by prevailing lassitude on 

 this question in the North, to get the rightfulness of 

 slavery recognised by the law and tradition of the whole 

 Union. In 1854 the " Missouri Compromise " was 

 repealed. The Republican Party then arose in the 

 North, pledged on the one hand to leave slavery un- 

 molested where it was already lawful, and on the 

 other to prevent its extension over any present or 

 future territory of the United States where it had not 

 been legalised already. In the State of Illinois great 

 service was done to the new party b}^ Abraham Lincoln, 

 a lawyer in fair practice, w-ho had been bom in 1809, 

 on the then frontier, in poor and rough surroundings. 

 He was distinguished as a youth equally by his physical 

 prowess and by his determined self-education, and 

 had entered early upon a political career which for 

 a while prospered, but had latterly lost interest in 

 politics. Lincoln's action henceforward was marked 

 by his reasoned and inflexible tenacity of both parts 

 of the Republican position. In i860 he proved to be 

 the most available candidate of his party for the 

 Presidency, and in November of that year was elected 

 President, owing to a split between the Southern 

 politicians and the party in the North which was 

 most favourable to them. Upon his election, seven 

 Southern " slave States " successively seceded from the 

 Union and formed a new Confederacy ; four more 

 slave States on the border joined them when hostilities 

 broke out ; while more adhered, as did all the " Free 

 States," to the Union. Lincoln entered office in March 



