284 



NA rURE 



[July 23, 1896 



of the air, and then the cloudiness, direction and velocity of 

 the wind ; whereas, for the ordinary moist earth, no matter 

 whether the surface is naked or covered with living plants, it 

 is the quantity of rain upon which the soil depends for its 

 moisture that is the important additional consideration. The 

 effects of the external elements on evaporation become less 

 important, as explained in paraj^raph 5, in proportion as the 

 precipitation is less and as the soil is more completely dried out 

 by the previous favourable weather, and vice versa. Vox these 

 reasons the rate of evaporation from a free surface of water not 

 infrequently differs largely from that from the respective kinds 

 of soil. 



(8) I'Vee surfaces of water, and soils that are continuously 

 saturated, evaporate into the atmosphere on the average more 

 water under otherwise similar circumstances than soils, whether 

 naked or covered with plants, and whether watered artiticially 

 or naturally. Only at special times, viz. when the influence of 

 the factors that favour evaporation is most intense, when the 

 plants are in the most active period of growth, and when the 

 soil contains a large percentage of water, can the land that is 

 covered with plants show a larger evaporating power than the 

 free-water surface. 



(9) When a soil that is not irrigated is covered with plants, it 

 evaporates a far greater quantity of moisture than when the sur- 

 face is bare. In the former case the evaporation can not exceed 

 the quantity received by the soil from the atmosphere before or 

 during the period of growth. Swampy lands and those that 

 are well irrigated, as also free surfaces of water, can, under cir- 

 cumstances favourable to evaporation, sometimes give to the 

 atmosphere a greater quantity of water than corresponds to the 

 precipitation that occurs during the same time. 



(10) The evaporating power of the soil is, in itself, dependent 

 upon its own physical properties ; the less its permeability for 

 water, or the larger its capacity for water and the easier it is 

 able to restore by capillarity the moisture that has been lost, by 

 so much the more intensive is the evaporation. For this reason 

 the quantity evaporated increases with the percentage of clay 

 and humus in the soil, whereas it diminishes in proportion as 

 the soil is richer in sandy and coarse-grained materials. 



(11) .Soil that is covered with plants loses by evaporation so 

 much more water in proportion as the plants are better developed, 

 or stand thicker together, or have a longer period of vegetation, 

 and vice versa. 



In conclusion, WoUny repeats that the use of apparatus giving 

 the total evaporation from free-water surfaces does not respond 

 to the needs of the agriculturist [and we may add of the meteor- 

 ologist], but that instruments must be used for measuring the 

 evaporation from masses of earth that are wet with rainfall only, 

 and free from stagnant wet soils. Lysimeters are recommended 

 having a section of one-tenth of a .square metre and a depth of soil 

 one-half of a meter, and set out in the open air, sunk ilush with 

 the surface of the ground, and arranged so as to be easily weighed 

 at any moment, and so that the drainage water can easily be 

 measured. 



The ft regoing results of Wollny's laborious observations confirm 

 us in the general conclusion that the quantity of water actually 

 evaporated from a large surface of land, such as a definite 

 watershed maintaining a single river, can only be determined by 

 the following considerations. The quantity of water contained 

 in the soil at the end of any given period in excess of what it 

 contained at the beginning, plus the water that is carried off by 

 drainage and river flow, plus whatever is evaporated into the 

 atmosphere either directly or through the crops and forests, must 

 equal the rain and irrigation water added to the soil during that 

 time. As the soil content of water, the riverflow and drainage, 

 and the rainfall can be severally determined by direct observa- 

 tion far better than the evaporation, the latter is to be determined 

 by taking the difference between the rainfall and all other sources 

 ol loss or consumption. 



LONDON UNIVERSITY COMMISSION BILL: 

 "D liFEKENCE was made in our issue of July 9, to the Bill 

 ■"•^ introduced by the Duke of Devonshire in the House of 

 Lords, for the purpose of appointing a statutory Commission to 

 make further provision with respect to the University of London. 

 The Bill reads as follows : — 



Whereas the Commissioners appointed to consider the draft 

 charter for the proposed Gresham University in London, have 



NO. 1395, VOL. 54] 



by their report made recommendations with respect to the re- 

 constitution of the University of London, and to the appointment 

 of a statutory Commission for that purpose : 



Be it therefore enacted by the (Queen's most Excellent 

 Majesty, by and with the advice and consent of the Lords 

 Spiritual and Temporal, and Commons, in this present 

 I'arliament assembled, and by the authority of the same, as 

 follows :— 



I. Appoiiiliiienl of Coiiiiiiissioners. — (l) There shall be a body 

 of Commissioners styled the University of London Com- 

 missioners, and consisting in the first instance of the following 

 persons [names not yet announced]. 



(2) If and whenever any vacancy occurs among the Commis- 

 sioners, it shall be lawful for Iler Alajesty the t^ueen to appoint 

 a person to fill the vacancy ; but the name of every person so 

 appointed shall be laid as soon as may be before both Houses of 

 Parliament. 



(3) The Commissioners may, with the consent of the Treasury 

 as to number, appoint or employ such persons as they may think 

 necessary for the execution of their duties under this Act, and 

 may remove any person so ajipointed or employed. 



(4) There shall be paid to any person so appointed or 

 employed such remuneration as the Treasury may assign, and 

 that remuneration and all expenses of the Commissioners 

 incurred with the sanction ol the Treasury in the execution of 

 this Act shall be paid out of moneys provided by Parliament. 



H. Duration and proceedings of Commissioners. — (l) The 

 powers of the Commissioners .shall continue until the end of the 

 year one thousand eight hundred and ninety-seven, and no 

 longer ; but it .shall be lawful for Her -Majesty the Queen, from 

 lime to time, with the advice of Her Privy jCouncil, on the 

 application of the Commissioners, to continue the powers of the 

 Commissioners for such time as Her M.ijesty thinks fit, but not 

 beyond the end of the year one thousand eight hundred and 

 ninety-eight. 



(2) The Commissioner first named in this Act shall be the 

 Chairman of the Commissioners ; and in case of his cea.sing from 

 any cause to be a Commissioner, or of his absence from any 

 meeting, the Commissioners present at each meeting shall choose 

 a chairman. 



(3) The powers of the Commissioners may be exercised al a 

 meeting at which three or more Commissioners are present. 



(4) In case of an equality of votes on a question at a meeting, 

 the chairman of the meeting shall have a second or casting vote 

 in respect of that question. 



(5) The Commissioners shall have a common seal which shall 

 be judicially noticed. 



(6) Any act of the Commissioners shall not be invalid by 

 reason only of any vacancy in their body ; but if at any time, 

 and as long as, the number of persons acting as Comniis.sioners 

 is less than four, the Commissioners shall discontinue the exercise 

 of their powers. 



III. Powers and duties of Commissioners. — (i) The Com- 

 missioners shall make statutes and regulations for the University 

 of London in general accordance with the scheme of the report 

 hereinbefore referred to, hut subject to any modifications which 

 may appear to them expedient after considering any representa- 

 tions made to ihem by the Senate or Convocation of the 

 University of London, or by any other body or persons affected. 



{2) In framing such .statutes and regulations, the Commis- 

 sioners shall see that provision is made for securing adequately 

 the interests of collegiate and non-collegiate students respec- 

 tively. 



(3) Statutes and regulations made under this Act shall have 

 efiect notwithstanding anything in any Act of Parliament, charter, 

 deed, or other instrument. 



I\'. Approval of statutes and regulations. — (i) When any 

 statute or regulation has been made by the Commissioners, a 

 notice of its having been made, and of the place where copies 

 of it can be obtained, shall be published in the London Gazette, 

 and the statute or regulation .shall be laid as soon as may be 

 before both Houses of I'arliament, and shall not be valid until 

 it has been approved by Her .Majesty the Queen in Council. 



(2) If either House of Parliament within forty days, exclusive 

 of any period of prorogation, after a statute or regulation has 

 been laid before it, presents an address praying the Queen to 

 withhold her assent from the statute or regulation, or any part 

 thereof, no further proceedings shall be taken on the statute or 

 regulation, or on the part thereof to which the address relates, 

 but this provision shall be without prejudice to the making of a 

 new statute or regulation. 



