660 PHILOSOPHICAL TRANSACTIONS. [aNNO 174g. 



As to the sex of the fish, it could not be judged of, nor of any internal part, 

 as the viscera had been taken out before he saw it, and all appearances destroyed 

 that might inform us; and therefore we must refer the reader to that curious 

 dissection of it made by Sir George Ent, as it is quoted by Charleton, in his 

 Mantissa Anatomica. 

 • Fig. 4, pi. 12, represented a back view of the rana piscatrix; aa, the bony 

 ridges and asperities between the eyes; from the central sulcus of which arise 

 bbb, the three virgae piscatoriae, or fishing rods; cc, the cirruli, or little webs, 

 all round the borders of the fish ; dd, the large humeral fins, under which are 

 the openings into the marsupia and branchiae; ee, the two posterior rods; f, the 

 posterior and superior spinal fin; g, the tail, which in this fish is vertical. 



Fig. 5 is a view of the under surface or belly of this fish; aa, the angles of 

 the lower jaw, seen and felt through the integuments; b, the skin or floor of the 

 mouth, capable of stretching into a sack, according to the bulk of the prey he 

 holds; cc, the fleshy live-fingered webs, by which they crawl on the bottoms of 

 shoals; dd, the openings into the marsupia and branchiae; e, the vent or anus; 

 f, the posterior and inferior spinal fin ; g, the cartilaginous branchiostegal bones. 



Fig. 6 is a view of the mouth, opened to show; a, the skin of the floor of 

 the mouth, as at b in fig. 5 ; b, the tongue ; cc, the external teeth in the upper 

 and under jaws, for holding the prey; dd, the corresponding clusters of teeth in 

 the inner cartilaginous jaw, for mastication, and tearing the prey ; ee, the rictus 

 oris; f, the upper jaw; g, the entrance into the gula and branchial holes. 



Fig. 7 is a full view of the opening into the marsupium, lying under the fin d. 



Observations on the Height to which Rockets ascend. By Mr. Benj. Robins, 



F.R.S. N°492, p. 131. 



The use of rockets may be so considerable in determining the position of dis- 

 tant places to each other, and in giving signals for naval or military purposes, 

 that it is worth while to examine what height they usually rise to, the better to 

 determine the extent of the country, through which they can be seen. There- 

 fore, at the exhibition of the late fire-works, Mr. R. desired a friend to observe 

 the angle of elevation to which the greatest part of them rose, and likewise the 

 angle made by the rocket or rockets, which should rise the highest of all. 



That friend was provided with an instrument, whose radius was 38 inches; 

 and, to avoid all uncertainty in its motion, it was fixed in an invariable position ; 

 and its field, which took in 10° of altitude, was divided by horizontal threads. 

 The station he chose was on the top of a house in King-street, Cheapside, where 

 he had a fair view of the upper part of the building erected in the Green Park. 

 There he observed that the single rockets which rose the most erect, were usually 

 elevated at their greatest height about Q\° above his level , and that among these 



