244 



Balances and Sets of Weights. Measurement of Time. 



No. :>i >;i;:i 



51 670, 51 674. 1 : 4 



51686. 1 : r,. 



Precision Weights, with No. Ill calibration, in polished walnut case, upholstered plush, * <i. 

 with fork and forceps, nickelled, the "twos" being in duplicate, Figure 51,670. 



List No. 51,669 51,670 51,671 



1 gram to 2 5 10 kg 



Price per Set 1. 17. 2. 17. 4. 12. 



Precision Weights, same construction as Nos. 51,669 51,671, but of Phosphor Bronze, with 

 No. I extra-fine calibration, Figure 51,674. 



List No. 51,673 51,674 51,675 



1 gram to 2 5 10 kg 



Price per Set 3. 3. 4. 13. 7. 10. 



The analytical weights are most carefully calibrated, the single weights in each set being in per- 

 fect agreement among each other. They are adapted for the most accurate physical and chemisal 

 weighings. 



The sets of weights with "Calibration I" have the accuracy required for Precision Check and 

 Ordinary Standards; they can replace the analytical weights in a number of cases. 



The sets with "Calibration II" have the accuracy required for Commercial Check Standards and 

 Standards for ordinary use; they are employed for physical weighing operations. 



The sets with "Calibration III" have the accuracy of the usual Precision and Medical Weights; 

 they are used in physical experiments in which absolute accuracy is not essential, e. g., hydrostatic 

 weighings. 



Calibrated Iron Weights. 



List No. 51,676 51,677 51,678 51,679 51,680 51,681 51,682 51,683 51,684 

 100 g 200 g 500 g 1 kg 2 kg 5 kg 10 kg 20 kg 50 kg 

 Each 0. 0. 7 0. 0. 8 0. 0. 9 0. 11. 0. 1.4 0. 2. 8 0. 4. 5 0. 9. 1. 0. 



Measurement of Time. 







;>l.;s<;. Sundial, simple form, Figure -'. 



51 687. Simple Gnomon for school use (Noack, Leitfaden, Fig. 6), see No. 51,494 .... 



51,688. Seconds Watch (Stop Watch or Chronoscope), Figure, keyless, "stop" and "zero" 

 positions, indicating 1 / 6 seconds 



51,68!). Alarm Clock, simple (M. T., Fig. 27) 



5 ],<>!<>. Alarm Clock with switch, Figure 



This clock is employed for breaking an electric circuit automatically after a definite time has 

 lapsed. The apparatus can be used with advantage in charging accumulators and in physical and 

 chemical work, etc. 



Cl. 22:t, 2013. 



