July 20, 1883.] 



• KNOVSALEDGE ♦ 



41 



Now let us endeavour to show what relation these pretty 

 shells hold to the bodies which have produced them. The 

 reports of the Chalhnyer expedition have shown that the 

 lladiolaria of the great oceans usually live towards the 

 surface, and that their skeletons, like those of the Glohi- 

 gerhm, are being continuously showered down on to the 

 bed of the deep sea from its surface waters. Unlike the 

 GlobiyerhuV; however, the Radiolaria prefer to live in the 

 temperate zones of the world; at about 55 deg. on either 

 side of the equator the Glohi<jerin(e commence to become 

 meagre in size, and to gradually disappear, whilst the 

 Radioluiiu increase in numbers and arrive at their climac- 

 teric towards the circumpolar areas, where they are super- 

 seded by Diatomaceous plants. 



The simplest form of Radiolarian is one which is common 

 in fresh-water ponds, the sun-aninialciili- (FiLr ~), or Actino- 



Fig. 7. .! ^ . ,, t,...iractile vacuoles. 



(From a drawing by H. K. Furrtst, in T. Bolton's Portfolio.) 



sphn'rium Eichltornii. This interesting creature, which has 

 been carefully studied by Hertwig and Lesser,* may often 

 be seen under the microscopes at Stand 75G in the Exhi- 

 bition. The tigure here given is reproduced from Mr. 

 Bolton's well-known portfolio of drawings. 



The Radiolaria are provided with still', usually straight, 

 but sometimes anastomosing pseudopodia, the coalescence 

 of which, however, can be immediately separated at the 

 will of the animal. The centre of the body possesses a 

 dense, protoplasmic capsule, which sometimes contains onl}' 

 a globule of oil, and there are one or more contractile 

 vacuoles in Aclinut-p/utrium, but not in the other forms. 

 The j)seudopodial protoplasm is everywhere studded with 

 yellowish celhiform bodies, which are .'aid to be composed 

 of a material like g/ycoffot, or animal starch, and it is in 

 this layer also that the beautiful siliceous skeleton is elabo- 

 rated. Aclinof))/i(iriiim does not generally possess any 

 skeleton, but some of its allies are providetl with spicules 

 of siliceous matter. 



Nearly all the Radiolaria are marine, of minute size, and 

 simple; but there are a few which live together and form 

 compound gi^Iatinoid masses at the surface of the sea, such 

 are Sphdrozoiim, Collosplid'ra, and Tlialassicolla. 



* Ueber Khizopoden, " Archiv fiir mikroskopiecho Aiiatoniio," 

 187G. 



In our next issue we propose to give a fully illustrated 

 account of tlie beautiful and useful sponges which adorn 

 many of the galleries in the Exhibition, to briefly point out 

 their aflinities, and to show the structural relationships 

 which exist between the living tissues of these curious 

 animals and the skeletons which are so much prized, both 

 for domestic purposes and as ornaments. 



{To he continued.) 



FLIGHT OF A VERTICAL MISSILE. 



By Richard A. Proctor. 



Prop. — A liody is projected vertically to a height, h, in 

 time t J (resistance of the air neglected). If we sum tip all 

 the westerly deflections due to the difference between the east- 

 wardly motion at points above the earth's surface, and at the 

 surface itself, w/iat total westerly deflection do we obtain ? 

 and how is the difference between the westerly deflection so 

 obtained and the real deflection to be exjilained I 



Consider only the fall of the body ; since manifestly the 

 westerly deflection obtained in this (incorrect) manner, 

 will be the same for the rise as for the fall. 



Let O be the point from which the body falls, gG^g the 



ground, OG=A=-i-. 



Let the falling body be at P after time /, then 0P=— , 



and GP=/t — — ■ In time dt the body at P is carried 



eastward with the eastwardly motion of G, while the point 

 P vertically above G is carried eastwards with the greater 

 motion due to the height of P above G. The motion of G 



in time dt is — ■'2T:r (where P is the earth's rotation period, 



and r the earth's radius). Therefore the q 



westerly deflection in time dt — 



= p[2r(»+/.--f)--Vr] 



Cons( ijuently, the total westerly deflection 

 during the fall, 



27rr htf\ 



Ml tl 



G 



or total westwardly deflection during ascent and descent, 

 Sjr/t 



= 3P'>- 



Let us try this problem another way. Put Y—.v, 



d.v 



P Q,=d.c. Then time of falling through P Q= , ; and 



V2gx 

 during this time the body gains a westerly deviation corre- 

 sponding to the excess of the eastwardly motion of the 



