SCIENTIFIC APPARATUS AND INSTRUMENTS FOR TESTING SAMPLES OF WATER AND SOIL IN AGRICULTURE, HORTICULTURE, FORESTRY AND ENVIRONMENTAL CONTROL, NAMELY, COMPARATORS, COLORIMETERS, PHOTOMETERS, PH METERS, TEST KITS CONSISTING PRIMARILY OF COMPARATORS FOR VISUAL COMPARISON, REAGENTS AND INDICATORS IN FORM OF TABLETS, POWDER OR LIQUID, COMPLETE AND READY FOR USE, FOR TESTING THE IONS OF WATER AND SOIL, NESSLERISERS, COLOR STANDARDS, TINTOMETERS, BACTERIO-LOGICAL TESTERS, CONDUCTIVITY METERS, TEMPERA...