Prior to CalCOFI's use of Guildline's Autosal and Portasal, different instrumentation or techniques were used to measure seawater sample salinities. When I first participated in cruises in the mid-1980's, salinities were collected in 250ml sample bottles with wire bail ceramic stoppers with rubber washer.  These samples were run on a Plessey (Hytech) Laboratory Salinometer. I went online to find out more about this particular instrument for our instrumentation timeline and was surprised at how little I found. Fortunately, I have a photocopy of the original Hytech manual so I scanned it to PDF. (JRW 06/2019)

In 1970, this salinometer was relabeled Plessey Model 6230 Portable Laboratory Salinometer by Plessey Environmental Systems.
("In 1970, Bissett-Berman was purchased by the British company Plessey Ltd. and the San Diego Division was renamed Plessey Environmental Systems. Ten years
later, Grundy bought the parent company of Plessey Environmental and a short time later phased out the oceanographic equipment.")

Salinity Sample bottle similar to what was used by CalCOFI in 1970-1990	Plessey/Hytech Laboratory Salinometer Model 6220 Manual (click for PDF of photocopy)