1242 Journal of Applied Microscopy 



shown across the river is the only view to be had of the nest from this near dis- 

 tance without having the foreground so full of limbs as to obscure the nest. 



The location is on the north end of Flathead lake, in western Montana. The 

 nest is in front of the University of Montana Biological Laboratory, which is 

 immediately behind the illustration. That is, it is at the photographer's back. 

 The river in the foreground is Swan river, or Big Fork. It is swift and turbu- 

 lent. There is no place on the opposite shore where the camera may be placed 

 so as to take in the nest. The nest is about a hundred feet from the ground. 



The picture with the nest small was taken on a Seed orthochromatic plate, on 

 a cloudy day when rain was falling. Without changing the camera the telephoto 

 lenses was added, and the camera was pointed so as to put the nest in the mid- 

 dle of a five by eight plate, and the magnification raised to five. Naturally the 

 exposure was porportionally longer. The sky was overcast, and rain was falling. 

 Indeed, it was necessary to notice that water did not get on the lens. Only the 

 small opening seen between the trees was taken by the telephoto, and the back- 

 ground was clouds. While a longer exposure would have produced a better result 

 for definition, the two pictures show how inaccessible objects become accessible 

 by the use of this lens. 



The pictures were taken in August, 1900. Many of these nests are found in 

 this vicinity, and it is said this nest has been used by wild geese in times past. 

 The nest has been used by ospreys for two years past, the birds being the objects 

 of study by the students at the summer laboratory. 

 University of Montana. MORTON J. ElrOD. 



MICRO-CHEMICAL ANALYSIS. 

 XII. 



THE ANALYTICAL REACTIONS OF GROUP II. 



Ca, Sr, Ba, — Gl, — Mg, Zn, Cd, Hg. 



CALCIUM. 



The following reagents will be found to be the most useful of those which 

 have been proposed for the detection of this element : 



I. Sulphuric acid. 



II. Oxalic acid. 



III. Sodium tartrate. 



IV. Potassium ferrocyanide. 

 V. Arsenic acid. 



VI. Primary sodium carbonate (HNaCO^). 



/. Dilute Sulphuric Acid added to solutions containing salts of Calcium, leads to- 

 the separation of hydrated Calcium Sulphate. 



CaCl2 + H2SO4 = CaSO^ . 2H2O + 2HC1. 

 Method.— ^o a drop of the solution to be tested, add a tiny drop of sulphuric 

 acid. In a few moments monoclinic crystals of calcium sulphate begin to form 



