134 VISCOUS THEORY OF GLACIER MOTION. [1846. 



March 1st 3rd, mild, with rain; 3rd 13th, cold; 15th, 

 heavy rain. Alternate rain and fine till end of the month. 

 27th. Not half a foot of snow lying at Chamouni. The source 

 of the Arveiron has not opened a vault. The quantity and 

 muddiness of the water the same as at the last report. 



April. First week fine ; second week cold with snow ; 

 changeable to the end of the month. 16th. Source of Arveiron 

 has not much increased in water since the middle of March. 

 In the end of April the snow first disappeared from the lower 

 part of both glaciers. 



May. The first half of the month fine, with occasional 

 snow ; the second half changeable, with rain. 1 7th. The 

 source of the Arveiron has increased three-fourths (means pro- 

 bably in the ratio of four to one) since the middle of April, and 

 is dirty. The ice-vault is not yet formed. 26th. The Glacier 

 des Bossons advances rapidly, and is crumbling into pyramids. 

 The end of the glacier is at least eighty-five feet high, and 

 advances considerably, particularly during the month of May ; 

 and widens greatly. 



June. A changeable and wet month ; a very late season.* 

 The snow did not entirely disappear from the Mer de Glace 

 opposite the Montanvert till the beginning of July. 6th, 7th. 

 The vault opened at the source of the Arveiron. The quantity 

 of water since the end of May is the usual summer supply. 



July. Commenced with warm weather. 5th. Thermo- 

 meter 27 Reaum. The snow has disappeared from the ice 

 opposite Montanvert, but some patches remain on the way to 

 the Jardin. The Mer de Glace is much higher in level (about 

 forty feet) than in former years, and the marks made in [the 

 rock at the Angle (in 1842) are all covered. The crevasses 

 much the same as usual. The glacier of Bossons has also in- 

 creased greatly, and appears to be approaching its old moraines. 

 The register for the greater part of July has not come to hand. 



August. A very changeable rainy month. 8th or 9th. 



* It will be seen from the temperature curves that the thermometer fell con- 

 siderably in the latter part of June, both at Geneva and St. Bernard. 



