lO 



NATURE 



[March 9, 192: 



Flowering Dates of Trees. 



Referring to Mr. J. E. Clark's interesting article 

 on the above subject in Nature of February i6, I 

 would suggest that a consideration of the different 

 variations of temperature between Falmouth and 

 London will help to solve the problem. From pheno- 

 logical observations I have made at Falmouth for 

 many years past, it would appear that on an average 

 this district is earlier than nearlj^ all other parts of 

 England in January and February by about a fort- 

 night, but that after those months the lead is lost 

 and the flowering and leafing of trees, etc., are re- 

 tarded by our situation being near the coast line, 

 where the waters of the European current play such 

 an important part in lowering the land temperatures 

 in summer and raising them in the winter. It is not 

 always sufficiently realised how much longer the sea 

 requires than the land to gain its summer heat and 

 then to lose it again. Thus we find from the records 

 of 41 years that the mean temperature of the sea in 

 December is 50-1°, whilst in January, February, 

 March, and April it is less, viz. 48-0°, 47-0°, 47-3°, and 

 49° respectively. 



The following table (1920 being taken at random) 

 shows that in January and February our mean tem- 

 perature is higher than about London, but during 

 March, April, and markedly in May, it falls behind 

 and it is only natural that the effect on the flowering 

 and leafing of trees, etc., should be as described by 

 Mr. Clark. 



Wii-SON Lloyd Fox. 

 Falmouth, February 24, 1922. 



Where did Terrestrial Life Begin? 



In reference to Mr. Dines's letter in Nature of 

 February 16, if the diurnal variations in temperature 

 and humidity on a mountain summit in the early 

 earth would have been smaller than at sea-level, my 

 objection to Dr. Macfie's theory would certainly not 

 hold. But Mr. Dines remarks that, assuming some 

 stratification of the atmosphere, the stirring up of 

 the lower levels might cause a temporary raising of 

 the temperature at higher levels, which is the basis 

 of my objection. Mr. Dines points out that if the 

 early atmosphere had been homogeneous, mountain 

 summits could not have been warmed by ascending 

 air, while if the air had been stratified vertical move- 

 ments would have been impossible ; but that dilemma 

 does not seem applicable to the conditions likely 

 when the earth had just cooled down to a temperature 

 at which life was possible. 



My conception of the probable geographical con- 

 ditions at the dawn of terrestrial life is that the 

 seas would have been small, but were growing from 

 water discharged from steam vents, which would 

 have kept the lower air hot and saturated. Above 

 the steam-charged layer the air temperature would 



NO. 2732, VOL. 109] 



have fallen quickly (as the surface would have 

 received less heat from the interior and have lost 

 more by radiation), so that the cooling by expansion 

 of air rising up a mountain side would have been 

 small and might have been largely counteracted by 

 latent heat set forth by the condensation of moisture. 

 Distrustful of my own capacity in thermodynamics, 

 some years ago I asked an expert on that subject, 

 in reference to another problem in primeval geography, 

 whether the last condition was possible, and he replied 

 that it was. The geographical conditions wliich 

 would seem most favourable for spontaneous genera- 

 tion from some inorganically formed carbohydrate 

 would be in a moist atmosphere in which the tempera- 

 ture would have been practically uniform. Unless 

 those conditions held on a mountain summit, some 

 lower position for the origin of life would seem more 

 probable. J. W. Gregory. 



February 20, 1922. 



The Name of the Gid Parasite. 



In 1910 (U.S. Dept. of Agriculture, Bureau of 

 Animal Industry, Bull. 125) Dr. Maurice C. Hall 

 published a most interesting historical account of the 

 gid parasite, a cestode worm which is exceedingly 

 destructive to sheep. He showed that the first avail- 

 able specific name for the worm was Taenia multiceps 

 of Leske, 1780. At the same time he rejected the 

 familiar name Coenurus of Rudolphi because Goeze 

 in 1782 had said that the parasite might be called 

 " Vielkopf {multiceps)." I protested at the time to 

 Dr. Hall that " multiceps " could scarcely be taken 

 as a vahd generic name. Goeze was not a binomial 

 writer ; he actually called the gid parasite Taenia 

 vesicularis cerebrina. Multiceps seems to have been 

 introduced simply as the Latin form of the common 

 name proposed, vielkopf. Now, after the passage of 

 years, I again have occasion to refer to the gid 

 parasite and I find no ground for altering my opinion. 

 Apparently the animal should be called Coenurus 

 multiceps (Leske). The matter is important, on 

 account of the injuries caused by the parasite, and 

 consequent frequent references to it. , I observe that 

 RailHet and Henry (191 5) and Railliet and MaruUaz 

 (19 1 9) accept multiceps as a valid generic name. 



T. D. A. Cockerell. 



University of Colorado, Boulder, Colorado. 



The Weathering of Mortar. 



In regard to statements in Nature of June 23 and 

 July 21, 1921 (vol. 107, pp. 523 and 652) to the 

 effect that the curious ridges and furrows which occur 

 in mortar in walls are due to the segregation of hme, 

 I would invite attention to a note in Proc. Dorset Nat. 

 Hist, and Antiq. Field Club, 1906, vol. xxvii. p. xxxii, 

 giving an account of an exhibit of mine of a series 

 of pieces of mortar from a wall showing the early 

 stages of the development of this phenomenon. 

 The appearance is caused by the growth of moss 

 in minute shrinkage cracks in the mortar, the sides 

 of the cracks being gradually disintegrated by the 

 roots of the moss, until the final stage of ridge and 

 furrow is reached and the moss, not having sufficient 

 root-hold, falls out when dry. 



I may add that since then I have tested the mortar 

 in the ridges and also some from the general body 

 below the surface, and can find no difference in the 

 proportion of lime contained in the two. 



Nelson M. Richardson. 



Montevideo, near Weymouth, February 24. 



