THE WOMBAT. 59 



Nimbus is a cloud without any definite shape from which 

 rain falls continually. Underneath we sometimes see small 

 loose clouds, fracto -cumulus, floating at a lower level. 



Besides the forms enumerated above, there are clouds of 

 daily ascending currents, viz. : — Cumulus (or woolpack) clouds^ 

 large globular rolling masses with a horizontal base, which 

 form again fracto-cumulus. 



Cumulo-nimbus, the thunder cloud, consists of heavy 

 masses rising in the form of mountains, having a fibrous- 

 sheet above, and a mass similar to nimbus below. 



Stratus may be described as a sheet of lifted fog ; when 

 broken by the wind it is termed fracto -stratus. 



In making observations it is necessary to take them as 

 near the zenith as possible, to avoid errors of perspective. 



It often happens that the clouds have the appearance of 

 regular striae, parallel and equi-distant, like waves on the 

 surface of water. This is mostly the case with the varieties 

 of cumulus. 



Simple undulations are clouds like ribs, in a slanting 

 direction, and they have been noticed to be forerunners of 

 very rough weather if they cross the zenith. 



Double undulation is like the simple, with fibrous clouds 

 running through it. Very rare. 



In summer all low clouds as a rule assume special forms 

 resembling, more or less, the cumulus. I wish specially to- 

 speak of one, called mammato -cumulus, very noticeable as 

 following simple undulations; whatever course these take, the 

 mammato follow, and woe betide us if they cross our zenith. 



OVER LAND AND SEA; 



OK 



DR. S. A. ANDREE'S AERIAL VOYAGE TO THE 

 NORTH POLE. 



By A. C. Macdonald, F.R.G.S. 



At about two o'Clockin the afternoon 11th July 1897, three intrepid 

 workers in scientific research started on an aerial voyage in the 

 balloon " Orner " — Eagle — for the North Pole. 



Dr. Andree and his companions left Nors-Koerna on the bay 

 of Danes in the isle of Amsterdam, north of Spitzbergen. This 

 expedition was long conceived and all the plans fully matured before 

 the dauntless Andree attempted to start He conceived his idea 

 about the same time that Nansen began to make his preparations- 



