316 



KNo\vij:nr,i- 



August, 1912. 



in tliffercnt diit-ctioiis; roKoiioratioii is due in all cases to the 

 fjrouih (if the actiM' outer tissues. 



^"endo {AiiiKiln <>/ Botany, \XV) has investigated the 

 early develnpnieiit of species of Laininaria, Coslaria, and 

 Uiiildriii, and adds considerably to previous records regarding 

 the stages from sporoling to adult plant in the Laminari.iccae. 

 The young plant is lilanicntoiis, growing by a single apical 

 cell, then longitudinal division occurs in the youngest segment 

 (the L-ut just below the apical cell) and the two cells thus 

 formcil, lying side by side, grow so that the upper part of the 

 plant becomes a single-layered expansion, supported on a 

 filamentous stalk. By further divisions, the expanded portion 

 or blade becomes two-layered, while the stalk becomes a 

 cylinder consisting of several rows of cells, while a meriste- 

 matic, or actively growing and dividing, zone appears at the 

 junction between blade and stalk. Apical growth gradually 

 diminishes as development proceeds, and finally ceases. A 

 single ■' pre-cortical " layer of large cells is developed at the 

 transition region, between the already existing two layers ; 

 then this precortex grows in thickness and sends inwards 

 thread-like outgrowths which give rise to the loose central 

 tissue or medulla. 



CHKMl.S IkV. 



Hy C. AixswoKTM MnciiiiLL, B.A. (Oxon.), F.I.C. 



SliNSITIVENESS OF BIRDS AND MICE TO CARBON 

 MONOXIDK.— A Technical Paper by Mr. G. A. Burrcll. 

 has just been published by the Bureau of Mines, Washington. 

 It is shown that the production of a cap upon the flame in a 

 safety lamp is not a reliable method of detecting the presence 

 of carbon monoxide in the gases in mines after explosions or 

 fires. A more sensitive means is to test the air with cuprous 

 chloride solution or with blood solution, though both of these 

 are inferior to the use of mice or small birds as indicators. 

 As an example, it is mentioned, that on one occasion Mr. 

 Burrell himself had remained for over twenty minutes in a 

 room, the atmosphere of which contained 0-25 per cent, of 

 carbon monoxide, and at the time experienced no ill-effects 

 beyond a slight headache, although subsequently he became 

 ill ; whereas canaries under the same conditions showed 

 indications of distress within a minute and fell down within 

 five minutes. Mice are also much more sensitive than human 

 beings to the action of the gas, though they do not show the 

 effects so soon as birds. The method has already shown its 

 value in practice, as is shown by the following mstance. /V 

 number of persons exploring a mine took with them a canary, 

 and on reaching a certain place the bird fell from its perch. 

 The party at once retreated without having suffered ill-effects, 

 although a subsecjuent analysis of the air at this spot showed 

 that it contained from 0-25 to 0-3 per cent, of carbon 

 monoxide. 



ACTION OF ACIDS ON CONCRETE.— The cause of 

 the rapid disintegration of concrete drains — in many cases 

 soon after they have been laid — has been investigated by Dr. 

 E. Neumann (Tonind. Zeit., 1912. XX.WI, 601). The 

 results of the experiments showed that in every instance the 

 concrete had been acted upon by an acid, either from without 

 or within. Thus, in one case the soil in which the concrete 

 was laid contained iron pyrites, by the decomposition of which 

 in the presence of the water in the soil, sulphuric acid was 

 produced. In other cases sulphuretted hydrogen within the 

 drains became partially oxidised to sulphuric acid. Other acids, 

 such as acetic, hydrochloric or oleic acid, also act upon con- 

 crete, though these are not likely to be of such common 

 occurrence as sulphuric acid. The latter appears to produce 

 its injurious effect by decomposing the aluminium and calcium 

 compounds in the concrete to form sulphates (especially 

 calcium sulphate), and in the production of these a considerable 

 increase in the volume of the material takes place. Acids also 

 act by converting some of the constituents of the concrete into 

 soluble salts, notably calcium bicarbonate, which are then 

 gradually dissolved by the water, so that the material falls to 

 piece" 



As a ri'medy it is suggested that the concrete should be 

 made of dense clinker .ind contain as little lime as possible, and 

 that the foundations of the drain and all exposed places should 

 be protected with asphalt or tar. In addition to these external 

 precautions means must be provided for the efTective ventila- 

 tion of the interior. 



GKOI.OGY. 



By G. \V. Tyrrell, A.R.C.Sc, F.G.S. 



A FORMER COURSE OF THE THAMES.— An inter- 

 esting suggestion as to a former course of the Thames is 

 made in a paper by Dr. R. L. Sherlock and Mr. A. H. Noble in 

 The Quarterly Journal of the Geological Society for June, 

 l'J12. They also deal with the clay -with -flints of Buckingham- 

 shire, which they believe to be of glacial origin. They regard 

 it as representing the product of the waste of ages of the 

 chalk and Eocene outliers, swept up by an ice-sheet from 

 the north or north-west, and spread out as the incoherent 

 material spoken of as the " clay-with-flints." If the chalk 

 solution theory of its origin be regarded as disproved, the 

 glacial theory is the only one consistent with the general 

 character of the deposit and the unworn nature of its flints. 

 The clay with flints is accompanied by a glacial gravel con- 

 sisting entirely of flint. It must be distinguished from the 

 fiuvioglacial or plateau-gravels generally lying at a lower level 

 and characterised by containing a certain amount of material 

 from distant sources. The plateau-gravels lie to the south 

 and south-east of the clay-with-flints area. The far-travelled 

 pebbles occur abundantly in a belt three to four miles wide. 

 running parallel with and including the present valley of the 

 Thames from Hurley to Bourne End, continuing in the same 

 east-north-east direction through Beaconsfield and Chalfont 

 to the Colne valley. These pebbles must have been brought 

 into their present position by the Thames, and their distribu- 

 tion seems to point to a former course of the Thames at the 

 foot of the Eocene escarpment from Bourne End to Rickmans- 

 worth, and from thence to Watford along the line of the 

 Colne, which occupies a part of the old valley. The level of 

 the gravels and the number of far-travelled pebbles fall oft 

 from the Thames towards Watford, and thus aftbrd corrobora- 

 tive evidence for this view. The diversion of the Thames 

 towards the south at Bourne End is believed to have been 

 accomplished by the movement of the ice-sheet across the old 

 Thames \alle_\', forcing the water to escape over a col by way 

 of Maidenhead. 



Pertinent criticism in the ensuing discussion turned upon 

 the definition of clay-with-flints and whether all clay-with- 

 flints — for example, that of Surrey — was to be regarded as of 

 glacial origin. The question was also asked whither the 

 authors proposed to send the Thames after it had reached 

 Watford — a question they preferred to leave unanswered until 

 they had examined the country east of Watford. 



METEOROLOGY. 



By John A. Curtis, F.R.Met.Soc. 



TiiK weather of the week ended June 15th, as set out in the 

 Weekly Weather Report issued by the Meteorological Office, 

 was very unsettled, with freiiuent rains. Thunderstorms were 

 reported on each of the first five days of the week, and these 

 were m many cases accompanied by heavy rain or hail. 



Temperature was below the average in all districts except 

 l-'ngland, E., but the variation was nowhere very great. The 

 highest readings reported were 73° at CuUompton and Camden 

 Square, and 71° at Greenwich and Southampton. \i Lerwick 

 the maximum for the week was only 52°, and at Wick 53°. 

 In Guernsey the maximum was 66°. The lowest readings 

 were 37° at Llandrindod Wells, and 39° at Cahir, Markree, 

 and Marlborough. On the grass the lowest readings reported 

 were 31° at Birmingham, and ii" at Buxton and Dublin 

 (Phoenix Park). 



The temperature of the soil at one foot depth was below the 

 average very generally ; at a depth of four teet it was almost 

 normal. 



