128 



KNOWLEDGE & SCIENTIFIC NEWS. 



[June, 1905. 



Although the question of the alteration in weight is not 

 yet settled, it is not premature to consider what is in- 

 volved in the acceptance of it. We have seen that it is 

 bound up with other questions. Its acceptance involves 

 that there shall also be a change in the mass of the body 

 or in its free acceleration under gravity, or in both. Not 

 long ago a possibility of the change in the mass of a 

 body would not have been considered even except with 

 great reluctance. The constancy of mass has been one 

 of the fundamental tenets of the creators of the present 

 state of physical science. Physicists of the Xineteentii 

 Century would have turned with preference to the alter- 

 native possibility. We shall consider these points in the 

 next part in connection with the electrical origin of mas-. 



{To be continued.) 



-j.^^.^^^ 



Star MqlP.— No. 2 



Pegasus. AndromedaL, and Pisces. 



.\s regards the general configuration of stars, the chiel 

 feature included in the present map is the " Square of 

 Pegasus " (although, be it remembered, one of the stars 

 is not in I'egasus). This will Le easily recognised near 

 the centre ot the map, and in the actual heavens is a 

 ready means of determining the true North. At the top ol 

 the map is the greater portion of Cassiopeia, which con- 

 stellation is included complete in Map 1. 



One of the most remarkable objects within this region 

 is the Great Nebula in Andromeda (R. A. oh. 3«m. Dec. 

 40' 45' N.), one of the itw visible to the naked eye. 

 This was tlie first nebula noted, having been described 

 long before telescopes were invented. It is of elliptical 

 shape, and when viewed in a powerful telescope it seems 

 to consist 01 a numb.r of rings with bright centre, pre- 

 senting an appearance somewhat similar to a hazy view 

 of Satarn. The spectrum of this nebula is continuous, 

 and would therefore be that derived from a large number 

 of stars of different compositions. Hence it has been 

 inferred that this object may ba in reality a vast group of 

 very distant stars, and not a gaseous neDula. hi i«S5 a 

 «' Nova " burst forth in this nel)ula. 



7 Andrcmeda (I. h. 5tm. + 4i''5i') is a fine triple star. 

 Two stars, magnitude 2i yellow, and 5J blue green, are 

 at a distance of io"-2, and the latter seen in a powerful 

 telescope resolves itself into a binary at a distance of 

 o"-45. Near this another peculiar nebula of very 

 elongated form occurs. 



o, T), and ' Cassiopeia, as well as 5 Cephci, are double stars, 

 the first and last named being also ■ ariables which have 

 already been referred to in the description of Map I. 



7 Arietis (I. h. 48m. + iS'49') is one of the earliest dis- 

 covered double stars, magnitude 4 2 and 4-4, distance 8"-3. 

 I Triangiili (II. h. 7m. + 29' 50') is a double star, one 

 5th magnitude yellow, the other 7th magnitude blue. 

 Distance 3"-5. 



tiCygm iXXI.h. 40m. + 2a'^i8') is a double star, of4th 

 and 5th magnitudes. Distance 2"-6 



^Aqiiarii [XXll. h. 24m. — o" 32';, double star, both of 

 4th magnitude. Distance 3"'i. 



(Star Map No. 1 (North Polar Regions) appeared in 

 the May number.) 



The Nation's Latest 

 Acquisition. 



By W. P. PvcK.\ir, A.L.ti., F.Z.S., &c. 

 " There are no examples of Dtplodocus at present in 

 the collection." Such is the statement to be found in 

 the Guide to the Geological Galleries of the British 

 Museum. To-day, thanks to the generosity of Mr. 

 Carnegie, this gap has been filled by the splendid gift 

 of a replica of the magnificent specimen of this enor- 

 mous creature in the Carnegie Museum at Pittsburg. 

 Since the Dinosaurs hold so important a place among 

 the reptiles, a short account of the remarkable speci- 

 men just added to our National Natural History 

 treasure-house may be of interest to many readers of 



" K.NOW LEDGE." 



Diplodocus Carnegii, as this specimen has been named, 

 represents one of the largest land animals known, 

 measuring some eighty-lour feel from lip of snout to 

 tip of tail, and between thirteen and fourteen feet high 

 at the top of the haunches. Of this enormous length, 

 over fifty feet belong to the tail, and about twenty to 

 the neck. .Apart from its great length, the vertebral 

 column is remarkable in several particulars. The neck 

 \ertebra', liftecn in number, recall those of birds, in 

 their great pneumaticity, as well as in the shape and 

 disposition of the cervical ribs. The neural spines of 

 Ine thorauic \ertebra; are of great height, as one would 

 expect from the great length of the neck. But the 

 caiidals, perhaps, are the most interesting. These 

 taper rapidly, terminating eventually in a number of 

 long cylindrical \ertcbra; forming a whip-like 

 termination to this appendage. W'hether this 

 peculiarity is the result of degeneration, or 

 whether of specialization to some peculiar function, 

 is not known, but the former is probably the case. At 

 the place where the tail first rests upon the ground two 

 separate sets of two vertebrae each are found to be 

 firmly fused together. Prof. Osborn suggests that 

 this fusion is the result of mechani- 

 Jcal strain brought aljout by the use 

 <>f the tail to form a tripod, inas- 

 (much as this beast, he believes, was 

 jin the habit of rearing itself upon 

 ',its hind legs, after the fashion of a 

 kangar(K). .\n cxamiii:ition of these 

 vertebral, however, rather 

 C<vv.>y seems to show that this 

 ' fusion is the result of injury. 

 The whole aspect of the 

 :;:ii:ral seems to contradict the 

 possibility of any such acrobatic 

 feats as standing erect. 



The pillar-shaped legs terminated 

 in five short, stout toes, of which 

 the three innermost on each foot 

 bore large claws, which, it is 

 significant to note, are twisted out- 

 wardly. The outermost digits 

 were clawless. 



The skull, which was about twf) 



feet in length, is curiously flattened, 



presents a rniinded muzzle, and an 



extraordinarily small brain cavity; 



so small, that the brain has been 



Kig... section 01 upper described as scarcely larger than a 



ol Diplodocus to large walnut ! Teeth were con- 



oi 'the t«iT"'°" fined to the fore part of the jaws, 



