| Name and Model Number | Keuffel & Esser 4175 Kurtz Psychrometric Slide Rule |
| Country of Origin | USA |
| Date of Manufacture | 1936 |
| Front Scales | TOTAL HEAT/LB.DRY AIR SAT, WET BULB AND DRY BULB [ DEW POINT AND DRY BULB, SENSIBLE HEAT B.T.U./LB.DRY AIR, PERCENT RELATIVE HUMIDTY ] DEW POINT AND DRY BULB, VAPOR PRESSURE IN. OF Hg, LBS./CU.FT. DRY AIR, LBS.DRY AIR/CU.FT.SAT.AIR, GRAINS/LB.DRY AIR SAT., GRAINS/CU.FT.SAT.AIR |
| Back Scales | Instructions for Use |
| Scale Length | 5" (12.5 cm) |
| Type of Rule | Slide Rule |
| Construction | Scales printed on white painted polished boxwood with K&E improved glass indicator. |
| Area of Use | Generic |
| Comment | For humidity and water vapor capacity calculations. |
| Rarity | RR |
| Donor | Collection of Dr. Paul J. Tarantolo Jr. |
| Match Number | 41 |
| Thumbnail (Click Picture for Details) |  |
| In conjunction with our 'donors' we assign a rarity rating to each item, based on the system devised by Herman van Herwijnen |
| (1929 - 2004), renowned Dutch collector, author, and creator of Herman's Archive, a collection of 5,000 slide rule images on CD. |
| • RR = Rare - 1 of 25 collectors has one; it may take a year to find an example in the marketplace. |
| • RRR = Very Rare - only a few known to collectors; may be several years before it comes up for sale. |
| • RRRR = Extremely Rare - a museum piece; unlikely that an example will come up for sale. |