Height of Clouds. 383 



real, abundant. — Caulfield. Toronto, very abundant. — 

 Brodie. 



Besides our native species of Gryllus, we have the well- 

 known House-cricket, Gryllus domesticus, Oliv., which has 

 been carried over in shipping from Europe. This creature 

 loves warm quarters, being found in kitchens and bake- 

 houses, where it feeds on crumbs and other scraps, not 

 being particular as regards diet. During the day it hides 

 in chinks and crevices, coming out at night in search of 

 food. During the summer it sometimes takes up temporary 

 quarters in the open air. 



Quebec, common. — Provancher. Montreal, common. — 

 Caulfield. Toronto, rare. — Brodie. 



The small black crickets that swarm in our meadows 

 belong to the genus Nemobius. They may be distinguished 

 from the species of Gryllus by the last joint of the palpi 

 being twice the length of the preceding joint, by their 

 smaller size, and by the thorax being slightly hairy. 



(To be continued.) 



Height of Clouds. 



By C. H. McLbod. 



The table given below contains the results of some obser- 

 vations on the height of clouds during the months of May 

 and June, 1886. The observers were J W. McOuat, B.A., 

 and Francis Topp, B.A. The method of work consisted in 

 simultaneous observations of altitude and azimuth. The 

 stations — McG-ill College Observatory (A) and the roof of 

 the City Hall (B) — gave a base of 6,300 feet. Communica- 

 tion between the observers was by the telephone. The 

 observations were reduced graphically, and as each set of 

 measurements gave two independent results, a gauge of 

 accuracy was obtained and wrong results from errors in 

 identification avoided. The precision with which such mea- 

 surement may be made, depends mainly on the possibility of 

 minutely describing the portion of cloud on which it is 

 esired to make the pointing. Otherwise the lines of colli- 



