78:
39:
31:
65:. This equipment works well under gentle, delicate and precise requirement. A policeman also comes in various sizes, shapes, and types. Some of them come in one-piece flexible plastic version and some in stainless. The origin of the policeman and its name cannot be identified for sure but some clues led back to the 19th century from German chemist
148:. This is less effective because dense precipitates may become compacted at the bottom of the beaker, while light precipitates may be dispersed on the walls of the beaker. A glass rod can be used to remove the precipitate but this risks poking a hole in the bottom of the beaker or scratching the beaker wall. In the 19th century, German chemist,
169:
The second speculation is the most likely the one since in the 1937 edition of Hackh's
Chemical Dictionary "platinum policeman," defined as "a platinum-iridium claw that fits over a glass rod and is used to hold a quantitative filter during ignition," which the purpose of the policeman was to prevent
159:
particles adhering to the glass must be removed by means of a so-called policeman, which is made by inserting the end of a rather thick large-sized glass stirring-rod into a short piece of rubber tubing. The rubber tube should be left protruding slightly beyond the end of the glass tube and sealed
85:
A policeman is generally a flexible natural-rubber blade attached to a glass rod, which is typically 5 mm to 6 mm diameter and 150 mm long. However, it also comes in various sizes and shapes depending on its uses. The rubber material provides chemical resistance. In some designs, there is no glass
95:
110:
A policeman can be used for cleaning the inside of glassware, or for getting the last bit of precipitate out of a vessel. Especially in chemical laboratories it is often used to transfer residues of precipitate or solid on glass surfaces when performing the gravimetric analysis.
165:
However, it seems that Olsen has nothing to do with the mass production and sales of this invention. Instead, Oesper
Collections catalog indicated that Henry Heil Company of St. Louis sold policemen as early as 1904.
101:
100:
97:
96:
102:
170:
the escape of stray filter paper from the crucible during the ignition process that causes thermal updrafts from the burner. Therefore, for policeman, it likely means to prevent the escape of stray precipitate.
99:
113:
It also used in biological laboratories, to transfer tissue culture cells from a plate to a suspension. It feature is to prevent the glass rod from scratching or breaking glassware.
303:
1532:
1511:
98:
1621:
1147:
296:
1208:
1185:
86:
rod, but instead the whole item is made of plastic or stainless steel and is shaped into a spatula or scraper shape at the end.
1645:
144:
funnel for separation from the supernatant liquid is required. This can be done by using a stream of distilled water from a
1640:
1476:
1365:
706:
289:
121:
There is no answer on where the name "policeman" comes from, though it may be related to the function of the instrument.
1180:
50:
is a hand-held flexible natural-rubber or plastic scraper. The common type of it is attached to a glass rod and used in
222:
155:
Then rubber policeman was also recorded in 1910 edition of J. C. Olsen's textbook of quantitative analysis that states
1650:
1256:
1225:
1137:
1380:
711:
782:
385:
128:
It is like the police in that it gathers up any stray or escaped particles of precipitate on the beaker wall.
1215:
1132:
596:
149:
66:
818:
566:
535:
136:
is essential. After precipitating the chemical element of interest, successfully transferring all of the
808:
686:
398:
1104:
764:
606:
237:
133:
62:
792:
601:
516:
453:
1319:
1302:
1241:
1142:
1066:
1002:
997:
915:
736:
189:
77:
1587:
1577:
1385:
1375:
1152:
956:
946:
941:
787:
701:
696:
448:
218:
152:
suggested a solution to overcome this problem using a device similar to the rubber policeman.
925:
890:
880:
872:
847:
831:
741:
648:
551:
443:
245:
42:
A type of policeman which is made of plastic and is formed into spatula shapes at the ends.
1602:
1329:
1195:
977:
951:
726:
621:
241:
1597:
1547:
1437:
1411:
1355:
1312:
1307:
1246:
905:
895:
556:
438:
403:
365:
350:
1634:
1542:
1421:
1251:
920:
857:
521:
355:
1582:
1370:
1334:
1261:
1157:
1127:
1122:
1050:
885:
671:
626:
543:
511:
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463:
393:
375:
54:
1496:
1324:
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1220:
1203:
1076:
1045:
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1025:
987:
862:
826:
676:
478:
433:
145:
137:
58:
38:
17:
274:. The University of California: P. Blakiston's son & co., inc. p. 564.
1501:
1491:
1442:
1360:
1172:
1017:
992:
852:
731:
691:
661:
616:
611:
591:
561:
458:
360:
312:
141:
30:
272:
Hackh's chemical dictionary: containing the words generally used in chemistry
106:
The use of a plastics policeman for raking the precipitate on the beaker wall
1592:
1390:
1040:
653:
468:
428:
370:
179:
1537:
1416:
1406:
1162:
1071:
1035:
716:
666:
51:
1557:
1552:
1350:
1007:
982:
972:
900:
721:
681:
281:
184:
249:
910:
125:
It is like the police in that it protects the beaker from scratching.
1527:
1506:
93:
76:
37:
29:
1081:
380:
1463:
1282:
1102:
762:
323:
285:
270:
Hackh, Ingo
Waldemar Dagobert; Grant, Julius (1937).
1570:
1520:
1474:
1430:
1399:
1343:
1295:
1234:
1194:
1171:
1115:
1059:
1016:
965:
934:
871:
840:
817:
801:
775:
641:
575:
487:
412:
334:
81:A picture of stainless steel laboratory policeman.
297:
8:
1257:Nuclear magnetic resonance (NMR) instrument
61:or solid on glass surfaces when performing
1484:
1471:
1460:
1292:
1279:
1112:
1099:
772:
759:
331:
320:
304:
290:
282:
1622:Instruments used in medical laboratories
213:
211:
209:
207:
205:
160:together with a little bicycle cement."
1138:Inductively coupled plasma (ICP) device
201:
1186:Transmission electron microscope (TEM)
7:
223:"The Origin of the Rubber Policeman"
1181:Scanning electron microscope (SEM)
25:
1226:Thermogravimetric analyzer (TGA)
1036:Nuclear magnetic resonance (NMR)
1:
230:Journal of Chemical Education
1667:
1619:
1487:
1470:
1459:
1381:Time-domain reflectometer
1291:
1278:
1148:Liquid chromatograph (LC)
1111:
1098:
771:
758:
330:
319:
57:to transfer residues of
1216:Melting-point apparatus
597:Cryogenic storage dewar
150:Carl Remigius Fresenius
67:Carl Remigius Fresenius
1646:Microbiology equipment
1153:Mass spectrometer (MS)
1143:Gas chromatograph (GC)
107:
82:
43:
35:
1528:Acid-resistant gloves
1209:differential scanning
105:
80:
41:
33:
1641:Laboratory equipment
1105:Analytical chemistry
607:Laminar flow cabinet
313:Laboratory equipment
134:gravimetric analysis
63:gravimetric analysis
1477:Personal protective
386:Meker–Fisher burner
242:2008JChEd..85..776J
1651:Chemical equipment
1320:Function generator
1303:Bench power supply
1242:Analytical balance
1003:Ostwald viscometer
998:Graduated cylinder
737:Inoculation needle
108:
83:
44:
36:
1628:
1627:
1615:
1614:
1611:
1610:
1588:Fire extinguisher
1578:Biosafety cabinet
1566:
1565:
1455:
1454:
1451:
1450:
1386:Transistor tester
1376:Spectrum analyzer
1274:
1273:
1270:
1269:
1094:
1093:
1090:
1089:
966:Measuring devices
788:Soxhlet extractor
754:
753:
750:
749:
702:Spectrophotometer
697:Pipeclay triangle
449:Mortar and pestle
250:10.1021/ed085p776
219:Jensen, William B
103:
16:(Redirected from
1658:
1485:
1472:
1461:
1366:Network analyzer
1293:
1280:
1113:
1100:
773:
760:
742:Inoculation loop
612:Microtiter plate
552:Test tube holder
444:Magnetic stirrer
332:
321:
306:
299:
292:
283:
276:
275:
267:
261:
260:
258:
256:
227:
215:
104:
34:Rubber policemen
21:
18:Rubber policeman
1666:
1665:
1661:
1660:
1659:
1657:
1656:
1655:
1631:
1630:
1629:
1624:
1607:
1603:Solvent cabinet
1562:
1533:Eyewash station
1516:
1481:
1479:equipment (PPE)
1478:
1466:
1447:
1426:
1395:
1339:
1330:Pulse generator
1296:Control devices
1287:
1266:
1230:
1196:Thermochemistry
1190:
1167:
1107:
1086:
1055:
1012:
978:Conical measure
961:
930:
867:
836:
813:
797:
767:
746:
727:Test tube brush
637:
622:Picotiter plate
585:
571:
567:Lab drying rack
526:Extension clamp
502:
483:
422:
408:
344:
326:
315:
310:
280:
279:
269:
268:
264:
254:
252:
225:
217:
216:
203:
198:
176:
119:
112:
94:
92:
75:
28:
27:Plastic scraper
23:
22:
15:
12:
11:
5:
1664:
1662:
1654:
1653:
1648:
1643:
1633:
1632:
1626:
1625:
1620:
1617:
1616:
1613:
1612:
1609:
1608:
1606:
1605:
1600:
1598:Safety cabinet
1595:
1590:
1585:
1580:
1574:
1572:
1568:
1567:
1564:
1563:
1561:
1560:
1558:Safety goggles
1555:
1553:Safety glasses
1550:
1548:Nitrile gloves
1545:
1543:Medical gloves
1540:
1535:
1530:
1524:
1522:
1518:
1517:
1515:
1514:
1509:
1504:
1499:
1494:
1488:
1482:
1475:
1468:
1467:
1464:
1457:
1456:
1453:
1452:
1449:
1448:
1446:
1445:
1440:
1438:Alligator clip
1434:
1432:
1428:
1427:
1425:
1424:
1419:
1414:
1412:Soldering iron
1409:
1403:
1401:
1397:
1396:
1394:
1393:
1388:
1383:
1378:
1373:
1368:
1363:
1358:
1356:Logic analyzer
1353:
1347:
1345:
1341:
1340:
1338:
1337:
1332:
1327:
1322:
1317:
1316:
1315:
1313:Voltage source
1310:
1308:Current source
1299:
1297:
1289:
1288:
1283:
1276:
1275:
1272:
1271:
1268:
1267:
1265:
1264:
1259:
1254:
1249:
1247:Colony counter
1244:
1238:
1236:
1232:
1231:
1229:
1228:
1223:
1218:
1213:
1212:
1211:
1200:
1198:
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1177:
1175:
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1168:
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1155:
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1135:
1130:
1125:
1119:
1117:
1109:
1108:
1103:
1096:
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1092:
1091:
1088:
1087:
1085:
1084:
1079:
1074:
1069:
1063:
1061:
1057:
1056:
1054:
1053:
1048:
1043:
1038:
1033:
1028:
1022:
1020:
1014:
1013:
1011:
1010:
1005:
1000:
995:
990:
985:
980:
975:
969:
967:
963:
962:
960:
959:
954:
949:
944:
938:
936:
932:
931:
929:
928:
923:
918:
913:
908:
903:
898:
893:
888:
886:Vacuum (Dewar)
883:
877:
875:
869:
868:
866:
865:
860:
855:
850:
844:
842:
838:
837:
835:
834:
829:
823:
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815:
814:
812:
811:
805:
803:
799:
798:
796:
795:
790:
785:
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777:
769:
768:
763:
756:
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751:
748:
747:
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739:
734:
729:
724:
719:
714:
709:
704:
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689:
684:
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674:
669:
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638:
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632:
629:
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619:
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594:
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586:
584:
583:
580:
576:
573:
572:
570:
569:
564:
559:
557:Test tube rack
554:
549:
546:
541:
538:
533:
532:Funnel support
530:
527:
524:
519:
514:
509:
505:
503:
501:
500:
497:
492:
488:
485:
484:
482:
481:
476:
471:
466:
461:
456:
451:
446:
441:
439:Liquid whistle
436:
431:
425:
423:
421:
420:
417:
413:
410:
409:
407:
406:
404:Vacuum dry box
401:
396:
391:
388:
383:
378:
373:
368:
366:Heating mantle
363:
358:
353:
351:Alcohol burner
347:
345:
343:
342:
339:
335:
328:
327:
324:
317:
316:
311:
309:
308:
301:
294:
286:
278:
277:
262:
200:
199:
197:
194:
193:
192:
187:
182:
175:
172:
132:In chemistry,
130:
129:
126:
118:
115:
91:
88:
74:
71:
26:
24:
14:
13:
10:
9:
6:
4:
3:
2:
1663:
1652:
1649:
1647:
1644:
1642:
1639:
1638:
1636:
1623:
1618:
1604:
1601:
1599:
1596:
1594:
1591:
1589:
1586:
1584:
1581:
1579:
1576:
1575:
1573:
1569:
1559:
1556:
1554:
1551:
1549:
1546:
1544:
1541:
1539:
1536:
1534:
1531:
1529:
1526:
1525:
1523:
1519:
1513:
1512:Safety shower
1510:
1508:
1505:
1503:
1500:
1498:
1495:
1493:
1490:
1489:
1486:
1483:
1480:
1473:
1469:
1462:
1458:
1444:
1441:
1439:
1436:
1435:
1433:
1429:
1423:
1422:Wire stripper
1420:
1418:
1415:
1413:
1410:
1408:
1405:
1404:
1402:
1398:
1392:
1389:
1387:
1384:
1382:
1379:
1377:
1374:
1372:
1369:
1367:
1364:
1362:
1359:
1357:
1354:
1352:
1349:
1348:
1346:
1342:
1336:
1333:
1331:
1328:
1326:
1323:
1321:
1318:
1314:
1311:
1309:
1306:
1305:
1304:
1301:
1300:
1298:
1294:
1290:
1286:
1281:
1277:
1263:
1260:
1258:
1255:
1253:
1252:Spiral plater
1250:
1248:
1245:
1243:
1240:
1239:
1237:
1233:
1227:
1224:
1222:
1219:
1217:
1214:
1210:
1207:
1206:
1205:
1202:
1201:
1199:
1197:
1193:
1187:
1184:
1182:
1179:
1178:
1176:
1174:
1170:
1164:
1161:
1159:
1156:
1154:
1151:
1149:
1146:
1144:
1141:
1139:
1136:
1134:
1131:
1129:
1126:
1124:
1121:
1120:
1118:
1116:Compositional
1114:
1110:
1106:
1101:
1097:
1083:
1080:
1078:
1075:
1073:
1070:
1068:
1065:
1064:
1062:
1058:
1052:
1049:
1047:
1044:
1042:
1039:
1037:
1034:
1032:
1029:
1027:
1024:
1023:
1021:
1019:
1015:
1009:
1006:
1004:
1001:
999:
996:
994:
991:
989:
986:
984:
981:
979:
976:
974:
971:
970:
968:
964:
958:
955:
953:
950:
948:
945:
943:
940:
939:
937:
933:
927:
924:
922:
919:
917:
914:
912:
909:
907:
904:
902:
899:
897:
894:
892:
889:
887:
884:
882:
879:
878:
876:
874:
870:
864:
861:
859:
856:
854:
851:
849:
846:
845:
843:
839:
833:
830:
828:
825:
824:
822:
820:
816:
810:
807:
806:
804:
800:
794:
791:
789:
786:
784:
781:
780:
778:
774:
770:
766:
761:
757:
743:
740:
738:
735:
733:
730:
728:
725:
723:
720:
718:
715:
713:
710:
708:
705:
703:
700:
698:
695:
693:
690:
688:
685:
683:
680:
678:
675:
673:
670:
668:
665:
663:
660:
658:Balance brush
657:
655:
652:
650:
647:
646:
644:
640:
634:Weighing dish
633:
631:Weighing boat
630:
628:
625:
623:
620:
618:
615:
613:
610:
608:
605:
603:
600:
598:
595:
593:
590:
589:
587:
581:
578:
577:
574:
568:
565:
563:
560:
558:
555:
553:
550:
547:
545:
542:
539:
537:
534:
531:
528:
525:
523:
522:Burette clamp
520:
518:
515:
513:
510:
507:
506:
504:
498:
496:
493:
490:
489:
486:
480:
477:
475:
472:
470:
467:
465:
462:
460:
457:
455:
452:
450:
447:
445:
442:
440:
437:
435:
432:
430:
427:
426:
424:
418:
415:
414:
411:
405:
402:
400:
397:
395:
392:
389:
387:
384:
382:
379:
377:
374:
372:
369:
367:
364:
362:
359:
357:
356:Bunsen burner
354:
352:
349:
348:
346:
340:
337:
336:
333:
329:
322:
318:
314:
307:
302:
300:
295:
293:
288:
287:
284:
273:
266:
263:
251:
247:
243:
239:
235:
231:
224:
220:
214:
212:
210:
208:
206:
202:
195:
191:
188:
186:
183:
181:
178:
177:
173:
171:
167:
163:
162:
158:
153:
151:
147:
143:
139:
135:
127:
124:
123:
122:
116:
114:
89:
87:
79:
72:
70:
68:
64:
60:
56:
53:
49:
40:
32:
19:
1583:Fire blanket
1521:Eye and hand
1507:Rubber apron
1371:Oscilloscope
1335:Potentiostat
1262:Plate reader
1158:pH indicator
1128:CHN analyzer
1123:AutoAnalyzer
916:Round-bottom
809:Boston round
672:Filter paper
627:Refrigerator
544:Retort stand
512:Clamp holder
508:Beaker clamp
474:Vortex mixer
469:Stirring rod
464:Static mixer
394:Teclu burner
271:
265:
253:. Retrieved
236:(776): 776.
233:
229:
168:
164:
161:
156:
154:
131:
120:
109:
84:
55:laboratories
47:
45:
1571:Other items
1497:Face shield
1344:Measurement
1325:Galvanostat
1285:Electronics
1235:Other items
1221:Thermometer
1204:Calorimeter
1133:Colorimeter
1077:Gas syringe
1060:Other items
988:Eye dropper
863:Watch glass
848:Evaporating
827:Cold finger
642:Other items
548:Screw clamp
540:Pinch clamp
529:Flask clamp
479:Wash bottle
434:Homogenizer
146:wash bottle
138:precipitate
59:precipitate
1635:Categories
1502:Respirator
1443:Test probe
1361:Multimeter
1173:Microscopy
993:Eudiometer
957:Separatory
926:Volumetric
891:Erlenmeyer
819:Condensers
783:Dean–Stark
732:Wire brush
692:Microscope
687:Centrifuge
662:Cork borer
617:Petri dish
592:Agar plate
579:Containers
562:Wire gauze
399:Water bath
361:Desiccator
255:13 October
196:References
142:filtration
1593:Fume hood
1538:Glove box
1391:Voltmeter
776:Apparatus
765:Glassware
654:Autoclave
649:Aspirator
602:Incubator
536:Iron ring
459:Sonicator
429:Chemostat
371:Hot plate
180:Glass rod
73:Structure
48:policeman
1492:Lab coat
1417:Tweezers
1407:Heat gun
1163:pH meter
1072:Bell jar
952:Dropping
906:Florence
896:Fernbach
858:Syracuse
717:Scoopula
667:Crucible
376:Lab oven
221:(2008).
174:See also
52:chemical
1431:General
1351:Ammeter
1051:Thistle
1008:Pipette
983:Cuvette
973:Burette
942:BĂĽchner
935:Funnels
921:Schlenk
901:Fleaker
881:BĂĽchner
802:Bottles
722:Spatula
712:Stopper
682:Forceps
582:Storage
499:Holders
419:Shakers
390:Striker
338:Heaters
325:General
238:Bibcode
185:Spatula
140:to the
1465:Safety
1067:Beaker
1046:Thiele
1031:Cragie
1026:Drying
947:Hirsch
911:Retort
873:Flasks
841:Dishes
832:Liebig
793:Kipp's
707:Splint
517:Tripod
495:Clamps
491:Stands
454:Shaker
416:Mixers
341:Dryers
190:Beaker
117:Origin
1400:Tools
1018:Tubes
853:Petri
226:(PDF)
1082:Vial
1041:Test
677:File
381:Kiln
257:2017
90:Uses
246:doi
1637::
244:.
234:85
232:.
228:.
204:^
69:.
46:A
305:e
298:t
291:v
259:.
248::
240::
157:"
20:)
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