Sept. 15, 1881J 



NATURE 



463 



from the district which is faulterl, and which shows di tinct 

 evidence of very recent elevation. 



Second Report of the Committee consisting of Prof. P. M. 

 Duncan and Mr. G. R. Vine, appointed for the purjose of re- 

 porting on Fossil Polyzoa ; draivn up hy Mr. Vin : — The order 

 is divided into three suljdivisions : — 



1. Chcilostoma, Baric. = Celleporina, Ehrenberg. 



2. Cyclos'omata, ,, ~ Tabullporim, Milne-Etl., ITagenow, 

 Johnston. 



3. Ctcnostomnta, ,, 



The foUowrng terms are u'^ed in this Report in describing the 

 genera : — 



ZOARIUM. — " The composite structure formed by repeated 

 gemmation " = Pulyzoarium and Polypidom of authors. 



ZocEClu.M or cell. — " The chamber ni which the Polypide is 

 lodged." 



CCENCECIUM. — "The common dermal system of a colony." 

 Applicable alike to the "Frond," or " I'olyzoary," of Fene- 

 stella, Polypora, Phyllo] era, or Synocladia : (.r to the associated 

 Zooecia and their connecting "interstitial tu'^uli," of Ctriopora, 

 Hyphasmaporn, and ArcIiKoprira, or species allied to these. 



Fenestrules. — The square, oblong, or partially rounded 

 openings in the zoarium — connected hy nohceliiilar dissepiments — 

 of Fenestella, Polypora, and species allied to these. 



Fenestr.I! applied to similar openings, whenever connected 

 by the general ^ubstance of the zcarium — as in Pbyllopora, 

 Clathropora, and the Permian Synocladia. 



Branches. — The CELL-bearing portions of the zoarium of 

 Glauconon.e, Fenestella, Polypora, or Synocladia ; or the off- 

 shoots from the main stem of any sf ecies. 



GON.ECIUM. — " A modified zcKcium or cell, set apart for the 

 purposes of reproduction." 



GoNOCYST. — "An inflation of the surface of the zoarium in 

 which the embryos nre developed." Modern terms from the 

 Rev. Thos. Hincks. 



Report of the Committee on Erratic Blocks, drawn up by the 

 Rev. B. VV. Crosskey. — Many additional instances of the occur- 

 rence of erratic Mi)cks were recorded. Particulars were given 

 respecting granite and sandstone boulders found while excavating 

 for the new dock at Maryi ort, Cumberland. The granite 

 specimens vary in size from small pebbles to a ton in weight, 

 and are rounded. The New Red Sandstone boulders vary from 

 half a ton to two tons or more, and have sharp angles. The 

 nearest granite occurs in the Kirkudbrightshire Hills, on the 

 other side of ihe Solway, fifteen or twenty miles distant; the 

 New Red Sand-tone is the stone of the district. A br ulder of 

 Shap granite found near Filey has been removed to the Uni- 

 versity Museum, Oxford. It rested on Oolitic stra'a at a height 

 of about 150 feet abjve the sea. The neare.^t place where a 

 granite of the same chiiracter is found is 108 miles distant, bear- 

 ing west-north-v.est from Filey. The attention of the committee 

 was drawn by Prof. T. McK. Hughes to a boulder of porphyritic 

 hornblende diabase, near the centre of Angle.' ea. It is chiefly 

 interesting p.s having been considartd an inscribed stone, but the 

 supposed characters are entirely due to rock structure. A 

 detailed description of the great erratic called the " Holy Stone," 

 at Humberstone, Leicestershire, was given. Its weight is about 

 twenty-one tons. It re>ts on a denuded surface of the Rha;tic 

 formation. The height from which it travelled is about 400 

 feet above the sea, and is situated six miles north-west. 

 The I resent height at which the block now rests is about 240 

 feet above the sen, and there is a river valley between these two 

 points, rui ning at right angles to the line of transit of the block, 

 which is only no feet above the level of the sea. Various 

 groups of boulders in Leicestershire were also described, some 

 containing millstone grit blocks derived from Derbyshire, 

 which must have travelled about thirty-five miles. A catalcgue 

 of 191 blocks in the parih of Ashwell, County of Hertford, was 

 given. None of these blocks are local. Their gener-1 deriva- 

 tion is from the Oolites of the Midlands and from the Carboni- 

 ferous and other rocks of more northern districts. The report 

 concluded with an appeal to local observers to give assistance 

 in cataloguing the rajidly-di- appearing err-tic blocks of the 

 country. 



Report OH Thermal Conductivity of Certain Rocks, shaioing espe- 

 cially tlu Geological Aspects of the Investigations, by Prof. A. S. 

 Herschel and Prof. Lebour. — This is the seventh and final 

 Report of the Committee, and comprises a rhum^ oi the results 

 given in the preceding ones, with numerous additions and correc- 



tions. A bibliographical list of all papers on the subject, by 

 Mr. J. T. Dunn, B.Sc, is given as an appendix. The appara- 

 tus and specimens employed during the investigations of the 

 Committee are preserved in the museum of the College of 

 Physical Science at Newcastle-on-Tyne. 



SECTION A— Mathematical and Physical 



On the Possibility of the Existence of Intra-Mercurial Planets, 

 by Balfour Stewart, LL.D., F.R.S. — It is a omewhat frequent 

 speculation amongst those who are engaged in sun-spot research 

 to regard the state of the solar surface as influenced in some way 

 by the positions of the planets. 



In order to verify this hypothesis o'^servers have tried whether 

 there appear to be solar periods exactly coinciding with certain 

 well-known planetary periods. This method has been adopted 

 by the Kew observers (Messrs. De La Rue, Stew.->rt, and 

 Loevi7), who had an unusually large mass of material at 

 their disposal, and they have obtained from it the following 

 results : — 



1. An apparent maximum and minimum of spotted area 

 approximately co-responding in time to the perihelion and 

 aphelion of Mercury. 



2. An apparent maximum and minimum of spotted area 

 approximately corresponding in time to the conjunction and 

 opposition of Mercury and Jupiter. 



3. An apparent maximum and minimum of spotted area 

 approximately corresponding in time to the conjunction and 

 opposition of Venus and Jupiter. 



4. An apparent maximum and minimum of spotted area 

 approximately corresponding in lime to the conjunction and 

 opposition of Venus and Mercury. 



The Kew observers make the following remarks u;on these 

 results : — 



"There appears to be a certain amount of likeness between 

 the march of the numbers in the four periods which we have 

 investigated, but we desire to record this rather as a result 

 brought out by a certain specified method of treating the 

 material at our disposal than as a fact from which we are at 

 present prepared to draw conclusions. As the investigation of 

 these and similar [ henomena proceed^, it may be hoped that 

 much light w ill be thrown upon the causes of sun-spot period- 

 icity." 



The Kew observers have likewise produced evidence of a 

 different kind in favour of the jlanetary hypothesis, for they 

 have detected a periodicity in the behaviour of sun-spots with 

 regard to increase and diminution apparently depending upon 

 the positions of the two nearer planets. Men ury and Venus. 

 The law seems to be that as a portion of the sun's surface is 

 carried by rotation nearer to one of these two influential planets, 

 there is a tendency for spots to become less and disappear, \> hile 

 on the other hand, when it is carried away from the neighbour- 

 hood of one of these planets, there is a tendency for spots to 

 break out and increase. 



But whatever truth may be in these conclusions, it appears 

 to be quite certain that periodical relations between the various 

 /5«ra;« planets will not account for n// the -un-spot inequalities 

 with which we are r.cquainted. They may accr unt for some, 

 but certainly not for all. For there are solar inequalities of 

 short dura' ion which, presuming them to be real, can only be 

 accounted for on the planetary hypothesis by supposing the 

 existence of several unknown intra-Mercurial planets. 



Indeed these short-period inequalities in sun-spots and the 

 allied phenomena of terrestrial magnetism and meteorology 

 have so augmented in number of late years as to make some 

 observers inclined to question their reality ; while others again 

 resort to the above-mentioned hypothesis, and attribute them to 

 intra-Mercurial phretary agency. 



The method to be pursued in detecting the existence of in- 

 equalities will be easily understood by an illustration. Suppose 

 that we had in our possession extensive records of the tempera- 

 lure of the earth's atmosphere at some one place in middle 

 latitudes, and that, independently of astronomical knowlef'ge, 

 we were to make u-e if thefe for the purpose of investigaimg 

 the natural inequalities of terrestrial temperature. We should 

 begin by grouping the observations according to various periods 

 taken, say, at ;m.nll but definite time-intervals fr^m each other. 

 Now if our series of obse'-vations were sufficiently extensive, 

 and if some one of cur various groupings together of this ^cries 



