CROMWELL 



1644 



CROOKES TUBES 



these volumes will give further Information as 

 to the life and times of Cromwell : 



Cavaliers 

 Charles, subheads 



Charles I and 



Charles II 

 Commonwealth of 



England 

 England 



Subtitle History 



Long Parliament 

 Marston Moor 

 Naseby, Battle of 

 Puritans 

 Restoration, The 

 Roundheads 

 Rump Parliament 

 Self-Denying Ordinance 



CROMWELL, THOMAS, Earl of Essex (about 

 1490-1540), an English statesman who rose to 

 power and influence through his willingness to 

 carry out the wholly selfish plans of Henry 

 VIII. Early in his career he gained the friend- 

 ship of Cardinal Wolsey (see WOLSEY, 

 THOMAS), who encouraged him to enter Parlia- 

 ment; there he successfully defended his pa- 

 tron against a bill of impeachment. Henry 

 VIII, observing his unusual ability, made him 

 his private secretary, and later conferred on 

 him a succession of offices, appointing him 

 Chancellor of the Exchequer, Lord of the 

 Privy Seal and Lord Chamberlain; finally, in 

 1540, he was created Earl of Essex. 



His submission to the king gave him undis- 

 puted authority in all the departments of ad- 

 ministration, and he carried out Henry's orders 

 for suppressing the monasteries so vigorously 

 that he was nicknamed the "Hammer of the 

 Monks." Cromwell at last fell a victim to 

 the whims of his royal master, for Henry, 

 conceiving a dislike for his third wife, Anne 

 of Cleves, took revenge on the Earl, who had 

 promoted the marriage, and allowed him to 

 be tried for treason. Thus, in the same year 

 that he received his title of nobility and 

 reached the summit of his honors, he was be- 

 headed. 



See HENRY, subhead Henry VIII, and refer- 

 ences there found to other articles in these vol- 

 umes. 



CROOKES, krooks, SIR WILLIAM (1832-19 1 9), 

 a distinguished English scientist whose chemical 

 and electrical discoveries and inventions have 

 given him a permanent place among the great 

 men in the field of science. He was born in 

 London, and after completing his education at 

 the Royal College of Chemistry became super- 

 intendent of the department of meteorology 

 at Radcliffe Observatory, Oxford University. 

 In 1855 he accepted the professorship of chem- 

 istry at Chester Training College. In 1859 

 he founded the Chemical News, and assumed 

 its editorship, 



Professor Crookes' experiments in electricity 

 led to his invention of the Crookes tubes 



(which see), widely used in the production of 

 X-rays. He was also the discoverer of the ele- 

 ment thallium, and of the sodium amalgam 

 process of separating gold and silver from their 

 ores (see AMAL- 

 GAM), and he de- 

 vised the radio- 

 meter (which 

 see). He was re- 

 garded as the 

 highest authority 

 on the applica- 

 tion of the laws 

 of chemistry to 

 the industrial 

 arts, and on mat- 

 ters of sanitation. 

 He was knighted 

 in 1897, was 

 awarded the Nobel 

 1907, served as foreign secretary of the Royal 

 Society from 1908 to 1912, and in 1914 was 

 elected president of that organization. 



The writings of Professor Crookes, which are 

 numerous, include A Practical Handbook of 

 Dyeing and Calico Printing, Select Methods 

 oj Chemical Analysis and Diamonds. 



CROOKES TUBES. Electricity will pass 

 through a vacuum more rapidly than through 

 the air. If the air be gradually exhausted from 

 a closed glass vessel through which an electric 

 current is passing, the spark caused by the cur- 



SIR WILLIAM CROOKES 

 prize for chemistry in 



4- 



rent gradually changes 

 to wavy lines and then 

 to a brush of light. 

 When the vacuum is 

 nearly complete the en- 

 tire vessel is filled with 

 light. Tubes or other 

 glass vessels from which 

 the air has been ex- 

 hausted and into the 

 opposite ends of which 

 platinum wires have 

 been sealed for elec- 

 trodes are known as 

 Crookes tubes. The ef- 

 fect can be secured by 

 attaching the electrodes 

 to the opposite poles of 

 an electric machine or 

 to an induction coil. A CROOKES TUBE 

 Smaller tubes containing different gases and 

 used as electric toys are known as Geissler's 

 tubes (which see). Crookes tubes are used in 

 the construction of apparatus for the produc- 



