Fig. 73.—Balance and Weights.
List of Apparatus used in Experiments
- 1 Crucible Tongs
- 2 Evaporating Dishes
- 1 Casserole
- 6 Beakers
- 12 Test Tubes
- 1 Wooden Stand
- 1 Test Tube Stand
- 1 Sand Bath
- 2 Funnels
- 1 Tripod
- 1 Stoddart Test Tube Clamp
- 1 Test Tube Brush
- 1 Burner and Tubing
- 2 Stirring Rods
- 6 Watch Glasses
- 2 Erlenmeyer Flasks
- 1 Package Filter Paper
- 1 Box Matches
- 1 Wire Gauze
- 2 Burettes
- 1 Porcelain Crucible
- 1 Aluminum Dish
Directions for Weighing.—Place the dish or material to be weighed in the left-hand pan of the balance. With the forceps lay a weight from the weight box on the right-hand pan. Do not touch the weights with the hands. If the weight selected is too heavy, replace it with a lighter weight. Add weights until the pans are counterpoised; this will be indicated by the needle swinging nearly as many divisions on one side of the scale as on the other. The brass weights are the gram weights. The other weights are fractions of a gm. The 500, 200, 100 mg. (milligram) weights are recorded as 0.5, 0.2, and 0.1 gm. The 50, 20, and 10 mg. weights as 0.05, 0.02, and 0.01 gm. If the 10, and 2 gm., and the 200, the 100, and the 50 mg. weights are used, the resulting weight is 12.35 gms. No moist substances should ever come in contact with the scale pans. The weights and forceps should always be replaced in the weight box. Too much care and neatness cannot be exercised in weighing.
Fig. 74.
