Describes a demonstration in which a ball is placed in an unstable position on a saddle shape. The ball becomes stable when it is rotated above some threshold angular velocity. The demonstration is a mechanical analog of confining a particle in a "Paul Trap". (DDR)

The creation of a simple, low-cost lock-in amplifier (LIA) suitable for use in the chemistry teaching laboratory is described. The use of integrated circuits and few components are necessary to adequately accomplish lock-in amplification limited the total cost of construction to under US$100.

Describes the desk top calculators now on the market, including manufacturers, prices, and functions performed. Provides a table of specifications for programmable desk calculators. (MLH)

Discussed and described are analytical instruments available for chemical analysis in 1940-41. (RH)

Suggestions for the design, installation, and operation of laboratory fume hoods are listed. (RH)

Describes the construction and use of an inexpensive, homemade polarimeter which can analyze optically active compounds. Ideas for activities using the apparatus are suggested. (JN)