L. E. KNOTT APPARATUS CO., BOSTON 386 ELECTROSCOPES … No. 83-135 No. 83-140 STUDENTS' ELECTROSCOPE, simple flask form $0.66 83-135 SIMPLE GOLD LEAF ELECTROSCOPE. This form is designed for teachers who desire a larger 83-140 and more substantial electroscope than the one immediately preceding. It is of the form shown in the illustration, with the…
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